Here are some specific htaccess examples taken mostly from my WordPress Password Protection plugin, which does alot more than password protection as you will see from the following mod_rewrite examples. These are a few of the mod_rewrite uses that BlogSecurity declared pushed the boundaries of Mod_Rewrite! Some of these snippets are quite exotic and unlike anything you may have seen before, also only for those who understand them as they can kill a website pretty quick.

Directory Protection

Enable the DirectoryIndex Protection, preventing directory index listings and defaulting. [Disable]

Options -Indexes
DirectoryIndex index.html index.php /index.php

Password Protect wp-login.php

Requires a valid user/pass to access the login page[401]

<Files wp-login.php>
Order Deny,Allow
Deny from All
Satisfy Any
AuthName "Protected By AskApache"
AuthUserFile /home/askapache.com/.htpasswda1
AuthType Basic
Require valid-user
</Files>

Password Protect wp-admin

Requires a valid user/pass to access any non-static (css, js, images) file in this directory.[401]

Options -ExecCGI -Indexes +FollowSymLinks -Includes
DirectoryIndex index.php /index.php
Order Deny,Allow
Deny from All
Satisfy Any
AuthName "Protected By AskApache"
AuthUserFile /home/askapache.com/.htpasswda1
AuthType Basic
Require valid-user
<FilesMatch "\.(ico|pdf|flv|jpg|jpeg|mp3|mpg|mp4|mov|wav|wmv|png|gif|swf|css|js)$">
Allow from All
</FilesMatch>
<FilesMatch "(async-upload)\.php$">
<IfModule mod_security.c>
SecFilterEngine Off
</IfModule>
Allow from All
</FilesMatch>

Protect wp-content

Denies any Direct request for files ending in .php with a 403 Forbidden.. May break plugins/themes [401]

RewriteCond %{THE_REQUEST} ^[A-Z]{3,9}\ /wp-content/.*$ [NC]
RewriteCond %{REQUEST_FILENAME} !^.+flexible-upload-wp25js.php$
RewriteCond %{REQUEST_FILENAME} ^.+\.(php|html|htm|txt)$
RewriteRule .* - [F,NS,L]

Protect wp-includes

Denies any Direct request for files ending in .php with a 403 Forbidden.. May break plugins/themes [403]

RewriteCond %{THE_REQUEST} ^[A-Z]{3,9}\ /wp-includes/.*$ [NC]
RewriteCond %{THE_REQUEST} !^[A-Z]{3,9}\ /wp-includes/js/.+/.+\ HTTP/ [NC]
RewriteCond %{REQUEST_FILENAME} ^.+\.php$
RewriteRule .* - [F,NS,L]

Common Exploits

Block common exploit requests with 403 Forbidden. These can help alot, may break some plugins. [403]

RewriteCond %{REQUEST_URI} !^/(wp-login.php|wp-admin/|wp-content/plugins/|wp-includes/).* [NC]
RewriteCond %{THE_REQUEST} ^[A-Z]{3,9}\ ///.*\ HTTP/ [NC,OR]
RewriteCond %{THE_REQUEST} ^[A-Z]{3,9}\ /.*\?\=?(http|ftp|ssl|https):/.*\ HTTP/ [NC,OR]
RewriteCond %{THE_REQUEST} ^[A-Z]{3,9}\ /.*\?\?.*\ HTTP/ [NC,OR]
RewriteCond %{THE_REQUEST} ^[A-Z]{3,9}\ /.*\.(asp|ini|dll).*\ HTTP/ [NC,OR]
RewriteCond %{THE_REQUEST} ^[A-Z]{3,9}\ /.*\.(htpasswd|htaccess|aahtpasswd).*\ HTTP/ [NC]
RewriteRule .* - [F,NS,L]

Stop Hotlinking

Denies any request for static files (images, css, etc) if referrer is not local site or empty. [403]

RewriteCond %{HTTP_REFERER} !^$
RewriteCond %{REQUEST_URI} !^/(wp-login.php|wp-admin/|wp-content/plugins/|wp-includes/).* [NC]
RewriteCond %{HTTP_REFERER} !^http://www.askapache.com.*$ [NC]
RewriteRule \.(ico|pdf|flv|jpg|jpeg|mp3|mpg|mp4|mov|wav|wmv|png|gif|swf|css|js)$ - [F,NS,L]

Safe Request Methods

Denies any request not using GET,PROPFIND,POST,OPTIONS,PUT,HEAD[403]

RewriteCond %{REQUEST_METHOD} !^(GET|HEAD|POST|PROPFIND|OPTIONS|PUT)$ [NC]
RewriteRule .* - [F,NS,L]

Forbid Proxies

Denies any POST Request using a Proxy Server. Can still access site, but not comment. See Perishable Press [403]

RewriteCond %{REQUEST_METHOD} =POST
RewriteCond %{HTTP:VIA}%{HTTP:FORWARDED}%{HTTP:USERAGENT_VIA}%{HTTP:X_FORWARDED_FOR}%{HTTP:PROXY_CONNECTION} !^$ [OR]
RewriteCond %{HTTP:XPROXY_CONNECTION}%{HTTP:HTTP_PC_REMOTE_ADDR}%{HTTP:HTTP_CLIENT_IP} !^$
RewriteCond %{REQUEST_URI} !^/(wp-login.php|wp-admin/|wp-content/plugins/|wp-includes/).* [NC]
RewriteRule .* - [F,NS,L]

Real wp-comments-post.php

Denies any POST attempt made to a non-existing wp-comments-post.php[403]

RewriteCond %{THE_REQUEST} ^[A-Z]{3,9}\ /.*/wp-comments-post\.php.*\ HTTP/ [NC]
RewriteRule .* - [F,NS,L]

HTTP PROTOCOL

Denies any badly formed HTTP PROTOCOL in the request, 0.9, 1.0, and 1.1 only[403]

RewriteCond %{THE_REQUEST} !^[A-Z]{3,9}\ .+\ HTTP/(0\.9|1\.0|1\.1) [NC]
RewriteRule .* - [F,NS,L]

SPECIFY CHARACTERS

Denies any request for a url containing characters other than "a-zA-Z0-9.+/-?=&" - REALLY helps but may break your site depending on your links. [403]

RewriteCond %{REQUEST_URI} !^/(wp-login.php|wp-admin/|wp-content/plugins/|wp-includes/).* [NC]
RewriteCond %{THE_REQUEST} !^[A-Z]{3,9}\ [a-zA-Z0-9\.\+_/\-\?\=\&]+\ HTTP/ [NC]
RewriteRule .* - [F,NS,L]

BAD Content Length

Denies any POST request that doesnt have a Content-Length Header[403]

RewriteCond %{REQUEST_METHOD} =POST
RewriteCond %{HTTP:Content-Length} ^$
RewriteCond %{REQUEST_URI} !^/(wp-admin/|wp-content/plugins/|wp-includes/).* [NC]
RewriteRule .* - [F,NS,L]

BAD Content Type

Denies any POST request with a content type other than application/x-www-form-urlencoded|multipart/form-data[403]

RewriteCond %{REQUEST_METHOD} =POST
RewriteCond %{HTTP:Content-Type} !^(application/x-www-form-urlencoded|multipart/form-data.*(boundary.*)?)$ [NC]
RewriteCond %{REQUEST_URI} !^/(wp-login.php|wp-admin/|wp-content/plugins/|wp-includes/).* [NC]
RewriteRule .* - [F,NS,L]

Missing HTTP_HOST

Denies requests that dont contain a HTTP HOST Header.[403]

RewriteCond %{REQUEST_URI} !^/(wp-login.php|wp-admin/|wp-content/plugins/|wp-includes/).* [NC]
RewriteCond %{HTTP_HOST} ^$
RewriteRule .* - [F,NS,L]

Bogus Graphics Exploit

Denies obvious exploit using bogus graphics[403]

RewriteCond %{HTTP:Content-Disposition} \.php [NC]
RewriteCond %{HTTP:Content-Type} image/.+ [NC]
RewriteRule .* - [F,NS,L]

No UserAgent, Not POST

Denies POST requests by blank user-agents. May prevent a small number of visitors from POSTING. [403]

RewriteCond %{REQUEST_METHOD} =POST
RewriteCond %{HTTP_USER_AGENT} ^-?$
RewriteCond %{REQUEST_URI} !^/(wp-login.php|wp-admin/|wp-content/plugins/|wp-includes/).* [NC]
RewriteRule .* - [F,NS,L]

No Referer, No Comment

Denies any comment attempt with a blank HTTP_REFERER field, highly indicative of spam. May prevent some visitors from POSTING. [403]

RewriteCond %{THE_REQUEST} ^[A-Z]{3,9}\ /.*/wp-comments-post\.php.*\ HTTP/ [NC]
RewriteCond %{HTTP_REFERER} ^-?$
RewriteRule .* - [F,NS,L]

Trackback Spam

Denies obvious trackback spam. See Holy Shmoly! [403]

RewriteCond %{REQUEST_METHOD} =POST
RewriteCond %{HTTP_USER_AGENT} ^.*(opera|mozilla|firefox|msie|safari).*$ [NC]
RewriteCond %{THE_REQUEST} ^[A-Z]{3,9}\ /.+/trackback/?\ HTTP/ [NC]
RewriteRule .* - [F,NS,L]

Map all URIs except those corresponding to existing files to a handler

RewriteEngine On
RewriteCond %{DOCUMENT_ROOT}%{REQUEST_URI} !-d
RewriteCond %{DOCUMENT_ROOT}%{REQUEST_URI} !-f
RewriteRule . /script.php

Map any request to a handler

In the case where all URIs should be sent to the same place (including potentially requests for static content) the method to use depends on the type of the handler. For php scripts, use: For other handlers such as php scripts, use:

RewriteEngine On
RewriteCond %{REQUEST_URI} !=/script.php
RewriteRule .* /script.php

And for CGI scripts:

ScriptAliasMatch .* /var/www/script.cgi

Map URIs corresponding to existing files to a handler instead

RewriteEngine On
RewriteCond %{DOCUMENT_ROOT}%{REQUEST_URI} -d [OR]
RewriteCond %{DOCUMENT_ROOT}%{REQUEST_URI} -f
RewriteCond %{REQUEST_URI} !=/script.php
RewriteRule .* /script.php

If the existing files you wish to have handled by your script have a common set of file extensions distinct from that of the hander, you can bypass mod_rewrite and use instead mod_actions. Let's say you want all .html and .tpl files to be dealt with by your script:

Action foo-action /script.php
AddHandler foo-action html tpl

Deny access if var=val contains the string foo.

RewriteCond %{QUERY_STRING} foo
RewriteRule ^/url - [F]

Removing the Query String

RewriteRule ^/url /url?

Adding to the Query String

Keep the existing query string using the Query String Append flag, but add var=val to the end.

RewriteRule ^/url /url?var=val [QSA]

Rewriting For Certain Query Strings

Rewrite URLs like http://askapache.com/url1?var=val to http://askapache.com/url2?var=val but don't rewrite if val isn't present.

RewriteCond %{QUERY_STRING} val
RewriteRule ^/url1 /url2

Modifying the Query String

Change any single instance of val in the query string to other_val when accessing /path. Note that %1 and %2 are back-references to the matched part of the regular expression in the previous RewriteCond.

RewriteCond %{QUERY_STRING} ^(.*)val(.*)$
RewriteRule /path /path?%1other_val%2

Mod_Rewrite Security originally appeared on AskApache.com

Unix file permissions are one of the more difficult subjects to grasp.. Well, ok maybe "grasp" isn't the word.. Master is the right word.. Unix file permissions is a hard topic to fully master, mainly I think because there aren't many instances when a computer user encounters them. Windows has been trying to figure it out for decades with little progress, so don't feel bad if you don't know much about it. Unless you're with the program and running Mac or any other BSD/Unix based OS you've never had the ability to secure your system in this most basic and fundamental way. Usually the first time someone encounters file permissions it's because their website was cracked..

.htaccess

$ chmod 604 .htaccess

604 -rw----r--  /home/askapache/cgi-bin/.htaccess

php.cgi

$ chmod 711 php.cgi

$ 711 -rwx--x--x  /home/askapache/cgi-bin/php.cgi

.php.ini

$ chmod 600 php.ini

$ 600 -rw-------  /home/askapache/cgi-bin/php.ini

I'm in the process of developing an updated version of the .htaccess security plugin, and one thing I have been working on is file permissions. Some people had problems trying to create files on their server and I realized it was bad programming on my part.. so I began researching permissions in detail. I went deep into the source code of Apache (which is why this site is called AskApache, BTW), PHP, Python, Ocaml, Perl, Ruby, and POSIX operating systems and got a pretty good handle on it now..

Tips before we dig in

Here's a few things I've learned that I didn't know before (using php).

Deleting Files and Directories

Deleting a file may require chmodding the file to 666 or even 777 before you are able to delete it. You also might have to chmod the parent directory of the file as well. Also, you may have to chdir to the directory the file is in. And lastly you may have to change the owner or group of the file. Further than that you can try renaming the file first then deleting it..

Deleting a directory means you need to remove every file in it first. It needs to be empty. And if your file system uses NFS or some other networked FS you might have even more problems deleting files. If the file you are trying to delete is being used by say, Apache or php then you might have to kill that process first.

Creating Files in Restrictive Environments

My research has been geared to try and make my code as robust as possible, I'm throwing everything but the kitchen sink into some of these functions because so many people are on such different types of servers. To create a file in a restrictive environment is a fun excercise to take.. You can write a file using many different functions, but there are some tricks if they all fail. One trick is instead of trying to "write" the data to the file, you can UPLOAD the data to the server and let PHP handle the file as if you used an upload form. I like to use fsockopen to do it, as some installations have been setup to prevent this type of fake upload.

Then there are the various other hacks like using an ftp connection (if you know the user/pass) to send the file from php, using ssh from php, whatever is available on the hosts php installation. In addition to those more involved workarounds you can often get around this problem by doing little hacks discussed at php.net in the comments for various functions. Such as changing the umask, changing directories with chdir first, creating a temporary file using a function like tempfile and then renaming or copying the tempfile to your desired file which sometimes gives you the permissions needed to write to the location.

If the php installation is newer than you can also look into creating your own stream context to pass write the data direct.

Stat Function

I've created a stat function in php that goes farther than the normal stat function... Just give the function a file to stat, and it returns an array of information.

function askapache_stat($filename) {
 clearstatcache();
 $ss=@stat($filename);
 if(!$ss) die("Couldnt stat {$filename}");
 $file_convert=array(0140000=>'ssocket',0120000=>'llink',0100000=>'-file',0060000=>'bblock',0040000=>'ddir',0020000=>'cchar',0010000=>'pfifo');
 $p=$ss['mode'];
 $t=decoct($ss['mode'] & 0170000);
 $str = (array_key_exists(octdec($t),$file_convert)) ? $file_convert[octdec($t)]{0} : 'u';
 $str.=(($p&0x0100)?'r':'-').(($p&0x0080)?'w':'-').(($p&0x0040)?(($p&0x0800)?'s':'x'):(($p&0x0800)?'S':'-'));
 $str.=(($p&0x0020)?'r':'-').(($p&0x0010)?'w':'-').(($p&0x0008)?(($p&0x0400)?'s':'x'):(($p&0x0400)?'S':'-'));
 $str.=(($p&0x0004)?'r':'-').(($p&0x0002)?'w':'-').(($p&0x0001)?(($p&0x0200)?'t':'x'):(($p&0x0200)?'T':'-'));
 
 $s=array(
 'perms'=>array(
  'umask'=>sprintf("%04o",umask()),
  'human'=>$str,
  'octal1'=>sprintf("%o", ($ss['mode'] & 000777)),
  'octal2'=>sprintf("0%o", 0777 & $p),
  'decimal'=>sprintf("%04o", $p),
  'fileperms'=>@fileperms($filename),
  'mode1'=>$p,
  'mode2'=>$ss['mode']),
 
 'filetype'=>array(
  'type'=>substr($file_convert[octdec($t)],1),
  'type_octal'=>sprintf("%07o", octdec($t)),
  'is_file'=>@is_file($filename),
  'is_dir'=>@is_dir($filename),
  'is_link'=>@is_link($filename),
  'is_readable'=> @is_readable($filename),
  'is_writable'=> @is_writable($filename)),
 
 'owner'=>array(
  'fileowner'=>$ss['uid'],
  'filegroup'=>$ss['gid'],
  'owner_name'=>(function_exists('posix_getpwuid')) ? @reset(@posix_getpwuid($ss['uid'])) : '',
  'group_name'=>(function_exists('posix_getgrgid')) ? @reset(@posix_getgrgid($ss['gid'])) : ''),
 
 'file'=>array(
  'filename'=>$filename,
  'realpath'=>(@realpath($filename) != $filename) ? @realpath($filename) : '',
  'dirname'=>@dirname($filename),
  'basename'=>@basename($filename)),
 
 'device'=>array(
  'device'=>$ss['dev'], //Device
  'device_number'=>$ss['rdev'], //Device number, if device.
  'inode'=>$ss['ino'], //File serial number
  'link_count'=>$ss['nlink'], //link count
  'link_to'=>($s['type']=='link') ? @readlink($filename) : ''),
 
 'size'=>array(
  'size'=>$ss['size'], //Size of file, in bytes.
  'blocks'=>$ss['blocks'], //Number 512-byte blocks allocated
  'block_size'=> $ss['blksize']), //Optimal block size for I/O.
 
 'time'=>array(
  'mtime'=>$ss['mtime'], //Time of last modification
  'atime'=>$ss['atime'], //Time of last access.
  'ctime'=>$ss['ctime'], //Time of last status change
  'accessed'=>@date('Y M D H:i:s',$ss['atime']),
  'modified'=>@date('Y M D H:i:s',$ss['mtime']),
  'created'=>@date('Y M D H:i:s',$ss['ctime'])),
 );
 
 clearstatcache();
 return $s;
}

PHP Stat Function Output

Example output, say from print_r(askapache_stat( __FILE__ ) );

Array(
[perms] => Array
  (
  [umask] => 0022
  [human] => -rw-r--r--
  [octal1] => 644
  [octal2] => 0644
  [decimal] => 100644
  [fileperms] => 33188
  [mode1] => 33188
  [mode2] => 33188
  )
 
[filetype] => Array
  (
  [type] => file
  [type_octal] => 0100000
  [is_file] => 1
  [is_dir] =>
  [is_link] =>
  [is_readable] => 1
  [is_writable] => 1
  )
 
[owner] => Array
  (
  [fileowner] => 035483
  [filegroup] => 23472
  [owner_name] => askapache
  [group_name] => grp22558
  )
 
[file] => Array
  (
  [filename] => /home/askapache/askapache-stat/public_html/ok/g.php
  [realpath] =>
  [dirname] => /home/askapache/askapache-stat/public_html/ok
  [basename] => g.php
  )
 
[device] => Array
  (
  [device] => 25
  [device_number] => 0
  [inode] => 92455020
  [link_count] => 1
  [link_to] =>
  )
 
[size] => Array
  (
  [size] => 2652
  [blocks] => 8
  [block_size] => 8192
  )
 
[time] => Array
  (
  [mtime] => 1227685253
  [atime] => 1227685138
  [ctime] => 1227685253
  [accessed] => 2008 Nov Tue 23:38:58
  [modified] => 2008 Nov Tue 23:40:53
  [created] => 2008 Nov Tue 23:40:53
  )
)

Every Permission 0000 to 0777

This shows what each numeric permission does to a REGULAR file. I'll provide the code to do this below so you can do the same thing on your server.

chmod 0

----------

chmod 1

---------x

chmod 2

--------w-

chmod 3

--------wx

chmod 4

-------r--

chmod 5

-------r-x

chmod 6

-------rw-

chmod 7

-------rwx

chmod 10

------x---

chmod 11

------x--x

chmod 12

------x-w-

chmod 13

------x-wx

chmod 14

------xr--

chmod 15

------xr-x

chmod 16

------xrw-

chmod 17

------xrwx

chmod 20

-----w----

chmod 21

-----w---x

chmod 22

-----w--w-

chmod 23

-----w--wx

chmod 24

-----w-r--

chmod 25

-----w-r-x

chmod 26

-----w-rw-

chmod 27

-----w-rwx

chmod 30

-----wx---

chmod 31

-----wx--x

chmod 32

-----wx-w-

chmod 33

-----wx-wx

chmod 34

-----wxr--

chmod 35

-----wxr-x

chmod 36

-----wxrw-

chmod 37

-----wxrwx

chmod 40

----r-----

chmod 41

----r----x

chmod 42

----r---w-

chmod 43

----r---wx

chmod 44

----r--r--

chmod 45

----r--r-x

chmod 46

----r--rw-

chmod 47

----r--rwx

chmod 50

----r-x---

chmod 51

----r-x--x

chmod 52

----r-x-w-

chmod 53

----r-x-wx

chmod 54

----r-xr--

chmod 55

----r-xr-x

chmod 56

----r-xrw-

chmod 57

----r-xrwx

chmod 60

----rw----

chmod 61

----rw---x

chmod 62

----rw--w-

chmod 63

----rw--wx

chmod 64

----rw-r--

chmod 65

----rw-r-x

chmod 66

----rw-rw-

chmod 67

----rw-rwx

chmod 70

----rwx---

chmod 71

----rwx--x

chmod 72

----rwx-w-

chmod 73

----rwx-wx

chmod 74

----rwxr--

chmod 75

----rwxr-x

chmod 76

----rwxrw-

chmod 77

----rwxrwx

chmod 100

---x------

chmod 101

---x-----x

chmod 102

---x----w-

chmod 103

---x----wx

chmod 104

---x---r--

chmod 105

---x---r-x

chmod 106

---x---rw-

chmod 107

---x---rwx

chmod 110

---x--x---

chmod 111

---x--x--x

chmod 112

---x--x-w-

chmod 113

---x--x-wx

chmod 114

---x--xr--

chmod 115

---x--xr-x

chmod 116

---x--xrw-

chmod 117

---x--xrwx

chmod 120

---x-w----

chmod 121

---x-w---x

chmod 122

---x-w--w-

chmod 123

---x-w--wx

chmod 124

---x-w-r--

chmod 125

---x-w-r-x

chmod 126

---x-w-rw-

chmod 127

---x-w-rwx

chmod 130

---x-wx---

chmod 131

---x-wx--x

chmod 132

---x-wx-w-

chmod 133

---x-wx-wx

chmod 134

---x-wxr--

chmod 135

---x-wxr-x

chmod 136

---x-wxrw-

chmod 137

---x-wxrwx

chmod 140

---xr-----

chmod 141

---xr----x

chmod 142

---xr---w-

chmod 143

---xr---wx

chmod 144

---xr--r--

chmod 145

---xr--r-x

chmod 146

---xr--rw-

chmod 147

---xr--rwx

chmod 150

---xr-x---

chmod 151

---xr-x--x

chmod 152

---xr-x-w-

chmod 153

---xr-x-wx

chmod 154

---xr-xr--

chmod 155

---xr-xr-x

chmod 156

---xr-xrw-

chmod 157

---xr-xrwx

chmod 160

---xrw----

chmod 161

---xrw---x

chmod 162

---xrw--w-

chmod 163

---xrw--wx

chmod 164

---xrw-r--

chmod 165

---xrw-r-x

chmod 166

---xrw-rw-

chmod 167

---xrw-rwx

chmod 170

---xrwx---

chmod 171

---xrwx--x

chmod 172

---xrwx-w-

chmod 173

---xrwx-wx

chmod 174

---xrwxr--

chmod 175

---xrwxr-x

chmod 176

---xrwxrw-

chmod 177

---xrwxrwx

chmod 200

--w-------

chmod 201

--w------x

chmod 202

--w-----w-

chmod 203

--w-----wx

chmod 204

--w----r--

chmod 205

--w----r-x

chmod 206

--w----rw-

chmod 207

--w----rwx

chmod 210

--w---x---

chmod 211

--w---x--x

chmod 212

--w---x-w-

chmod 213

--w---x-wx

chmod 214

--w---xr--

chmod 215

--w---xr-x

chmod 216

--w---xrw-

chmod 217

--w---xrwx

chmod 220

--w--w----

chmod 221

--w--w---x

chmod 222

--w--w--w-

chmod 223

--w--w--wx

chmod 224

--w--w-r--

chmod 225

--w--w-r-x

chmod 226

--w--w-rw-

chmod 227

--w--w-rwx

chmod 230

--w--wx---

chmod 231

--w--wx--x

chmod 232

--w--wx-w-

chmod 233

--w--wx-wx

chmod 234

--w--wxr--

chmod 235

--w--wxr-x

chmod 236

--w--wxrw-

chmod 237

--w--wxrwx

chmod 240

--w-r-----

chmod 241

--w-r----x

chmod 242

--w-r---w-

chmod 243

--w-r---wx

chmod 244

--w-r--r--

chmod 245

--w-r--r-x

chmod 246

--w-r--rw-

chmod 247

--w-r--rwx

chmod 250

--w-r-x---

chmod 251

--w-r-x--x

chmod 252

--w-r-x-w-

chmod 253

--w-r-x-wx

chmod 254

--w-r-xr--

chmod 255

--w-r-xr-x

chmod 256

--w-r-xrw-

chmod 257

--w-r-xrwx

chmod 260

--w-rw----

chmod 261

--w-rw---x

chmod 262

--w-rw--w-

chmod 263

--w-rw--wx

chmod 264

--w-rw-r--

chmod 265

--w-rw-r-x

chmod 266

--w-rw-rw-

chmod 267

--w-rw-rwx

chmod 270

--w-rwx---

chmod 271

--w-rwx--x

chmod 272

--w-rwx-w-

chmod 273

--w-rwx-wx

chmod 274

--w-rwxr--

chmod 275

--w-rwxr-x

chmod 276

--w-rwxrw-

chmod 277

--w-rwxrwx

chmod 300

--wx------

chmod 301

--wx-----x

chmod 302

--wx----w-

chmod 303

--wx----wx

chmod 304

--wx---r--

chmod 305

--wx---r-x

chmod 306

--wx---rw-

chmod 307

--wx---rwx

chmod 310

--wx--x---

chmod 311

--wx--x--x

chmod 312

--wx--x-w-

chmod 313

--wx--x-wx

chmod 314

--wx--xr--

chmod 315

--wx--xr-x

chmod 316

--wx--xrw-

chmod 317

--wx--xrwx

chmod 320

--wx-w----

chmod 321

--wx-w---x

chmod 322

--wx-w--w-

chmod 323

--wx-w--wx

chmod 324

--wx-w-r--

chmod 325

--wx-w-r-x

chmod 326

--wx-w-rw-

chmod 327

--wx-w-rwx

chmod 330

--wx-wx---

chmod 331

--wx-wx--x

chmod 332

--wx-wx-w-

chmod 333

--wx-wx-wx

chmod 334

--wx-wxr--

chmod 335

--wx-wxr-x

chmod 336

--wx-wxrw-

chmod 337

--wx-wxrwx

chmod 340

--wxr-----

chmod 341

--wxr----x

chmod 342

--wxr---w-

chmod 343

--wxr---wx

chmod 344

--wxr--r--

chmod 345

--wxr--r-x

chmod 346

--wxr--rw-

chmod 347

--wxr--rwx

chmod 350

--wxr-x---

chmod 351

--wxr-x--x

chmod 352

--wxr-x-w-

chmod 353

--wxr-x-wx

chmod 354

--wxr-xr--

chmod 355

--wxr-xr-x

chmod 356

--wxr-xrw-

chmod 357

--wxr-xrwx

chmod 360

--wxrw----

chmod 361

--wxrw---x

chmod 362

--wxrw--w-

chmod 363

--wxrw--wx

chmod 364

--wxrw-r--

chmod 365

--wxrw-r-x

chmod 366

--wxrw-rw-

chmod 367

--wxrw-rwx

chmod 370

--wxrwx---

chmod 371

--wxrwx--x

chmod 372

--wxrwx-w-

chmod 373

--wxrwx-wx

chmod 374

--wxrwxr--

chmod 375

--wxrwxr-x

chmod 376

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chmod 377

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chmod 400

-r--------

chmod 401

-r-------x

chmod 402

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chmod 403

-r------wx

chmod 404

-r-----r--

chmod 405

-r-----r-x

chmod 406

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chmod 407

-r-----rwx

chmod 410

-r----x---

chmod 411

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chmod 412

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chmod 413

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chmod 414

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chmod 415

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chmod 416

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chmod 417

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chmod 420

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chmod 421

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chmod 422

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chmod 423

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chmod 424

-r---w-r--

chmod 425

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chmod 426

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chmod 427

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chmod 430

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chmod 431

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chmod 432

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chmod 434

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chmod 437

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chmod 440

-r--r-----

chmod 441

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chmod 444

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chmod 445

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chmod 446

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chmod 447

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chmod 450

-r--r-x---

chmod 451

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chmod 452

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chmod 453

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chmod 454

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chmod 455

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chmod 456

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chmod 457

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chmod 460

-r--rw----

chmod 461

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chmod 462

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chmod 463

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chmod 471

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chmod 472

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chmod 473

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chmod 474

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chmod 475

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chmod 476

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chmod 477

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chmod 500

-r-x------

chmod 501

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chmod 502

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chmod 503

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chmod 504

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chmod 505

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chmod 511

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chmod 512

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chmod 513

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chmod 514

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chmod 515

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chmod 561

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chmod 562

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chmod 563

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chmod 564

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chmod 565

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chmod 566

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chmod 567

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chmod 570

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chmod 571

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chmod 572

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chmod 573

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chmod 574

-r-xrwxr--

chmod 575

-r-xrwxr-x

chmod 576

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chmod 577

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chmod 600

-rw-------

chmod 601

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chmod 602

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chmod 603

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chmod 604

-rw----r--

chmod 605

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chmod 606

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chmod 607

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chmod 610

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chmod 611

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chmod 612

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chmod 613

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chmod 614

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chmod 615

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chmod 616

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chmod 617

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chmod 620

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chmod 621

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chmod 622

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chmod 623

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chmod 624

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chmod 627

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chmod 630

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chmod 632

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chmod 633

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chmod 634

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chmod 635

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chmod 636

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chmod 637

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chmod 640

-rw-r-----

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chmod 642

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chmod 644

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chmod 645

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chmod 647

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chmod 650

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chmod 651

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chmod 652

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chmod 653

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chmod 654

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chmod 655

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chmod 656

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chmod 657

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chmod 660

-rw-rw----

chmod 661

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chmod 662

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chmod 664

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chmod 665

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chmod 667

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chmod 670

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chmod 672

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chmod 673

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chmod 674

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chmod 675

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chmod 676

-rw-rwxrw-

chmod 677

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chmod 700

-rwx------

chmod 701

-rwx-----x

chmod 702

-rwx----w-

chmod 703

-rwx----wx

chmod 704

-rwx---r--

chmod 705

-rwx---r-x

chmod 706

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chmod 707

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chmod 710

-rwx--x---

chmod 711

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chmod 712

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chmod 713

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chmod 714

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chmod 715

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chmod 716

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chmod 717

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chmod 720

-rwx-w----

chmod 721

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chmod 722

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chmod 723

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chmod 724

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chmod 725

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chmod 726

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chmod 727

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chmod 730

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chmod 731

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chmod 732

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chmod 733

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chmod 734

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chmod 735

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chmod 736

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chmod 737

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chmod 740

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chmod 741

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chmod 742

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chmod 743

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chmod 744

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chmod 745

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chmod 746

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chmod 747

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chmod 750

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chmod 751

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chmod 752

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chmod 753

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chmod 754

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chmod 755

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chmod 756

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chmod 757

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chmod 760

-rwxrw----

chmod 761

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chmod 762

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chmod 763

-rwxrw--wx

chmod 764

-rwxrw-r--

chmod 765

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chmod 766

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chmod 767

-rwxrw-rwx

chmod 770

-rwxrwx---

chmod 771

-rwxrwx--x

chmod 772

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chmod 773

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chmod 774

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chmod 775

-rwxrwxr-x

chmod 776

-rwxrwxrw-

chmod 777

-rwxrwxrwx

Congratulations!

Here's my custom stat function, which I am definately not finished with, so check back in a couple days and if you find any improvements please hook me up with a comment!

function askapache_stat( $filename ) {
$p=@fileperms($filename);
$s=@stat($filename);
$str='';
$t=decoct($s['mode'] & 0170000);
 
switch (octdec($t)) {
case 0140000: $str = 's'; $stat['type']='socket'; break;
case 0120000: $str = 'l'; $stat['type']='link'; break;
case 0100000: $str = '-'; $stat['type']='file'; break;
case 0060000: $str = 'b'; $stat['type']='block'; break;
case 0040000: $str = 'd'; $stat['type']='dir'; break;
case 0020000: $str = 'c'; $stat['type']='char'; break;
case 0010000: $str = 'p'; $stat['type']='fifo'; break;
default: $str = 'u'; $stat['type']='unknown'; break;
}
 
$stat['type_octal'] = sprintf("%07o", octdec($t));
 
$str .= (($p&0x0100)?'r':'-').(($p&0x0080)?'w':'-').(($p&0x0040)?(($p&0x0800)?'s':'x'):(($p&0x0800)?'S':'-'));
$str .= (($p&0x0020)?'r':'-').(($p&0x0010)?'w':'-').(($p&0x0008)?(($p&0x0400)?'s':'x'):(($p&0x0400)?'S':'-'));
$str .= (($p&0x0004)?'r':'-').(($p&0x0002)?'w':'-').(($p&0x0001)?(($p&0x0200)?'t':'x'):(($p&0x0200)?'T':'-'));
 
$stat['default_umask']=sprintf("%04o",umask());
$stat['perm_human']=$str;
$stat['perm_octal1'] = sprintf( "%o", ( $s['mode'] & 00777 ) );
$stat['perm_octal2'] = sprintf("0%o", 0777 & $p);
$stat['perm_dec'] = sprintf("%04o", $p);
$stat['perm_mode']=$s['mode'];   // File mode.
 
$stat['file'] = @realpath($filename);
$stat['basename'] = basename( $filename );
 
$stat['user_id'] = $s['uid'];
$stat['group_id'] = $s['gid'];
 
$stat['device']=$s['dev'];      // Device
$stat['device_number']=$s['rdev'];    // Device number, if device.
$stat['inode']=$s['ino'];      // File serial number
$stat['link_count']=$s['nlink'];    // link count
if($stat['type']=='link')$stat['link_to']=@readlink( $filename );
 
$stat['size']=$s['size'];    // Size of file, in bytes.
$stat['block_size']=$s['blksize'];  // Optimal block size for I/O.
$stat['blocks']=$s['blocks'];  // Number 512-byte blocks allocated
 
$stat['time_access']=@date( 'Y M D H:i:s',$s['atime']);    // Time of last access.
$stat['time_modified']=@date( 'Y M D H:i:s',$s['mtime']);    // Time of last modification
$stat['time_created']=@date( 'Y M D H:i:s',$s['ctime']);    // Time of last status change
 
clearstatcache();
return $stat;
}
 
header('Content-Type: text/plain');
$stat=askapache_stat(__FILE__);
print_r($stat);

Defining Permission Bits

!defined('S_IFMT') && define('S_IFMT', 0170000); //  mask for all types
!defined('S_IFSOCK') && define('S_IFSOCK', 0140000); // type: socket
!defined('S_IFLNK') && define('S_IFLNK', 0120000); // type:  symbolic link
!defined('S_IFREG') && define('S_IFREG', 0100000); // type:  regular file
!defined('S_IFBLK') && define('S_IFBLK', 0060000); // type:  block device
!defined('S_IFDIR') && define('S_IFDIR', 0040000); // type:  directory
!defined('S_IFCHR') && define('S_IFCHR', 0020000); // type:  character device
!defined('S_IFIFO') && define('S_IFIFO', 0010000); // type:  fifo
 
!defined('S_ISUID') && define('S_ISUID', 0004000); // set-uid bit
!defined('S_ISGID') && define('S_ISGID', 0002000); // set-gid bit
!defined('S_ISVTX') && define('S_ISVTX', 0001000); // sticky bit
!defined('S_IRWXU') && define('S_IRWXU', 00700); //  mask for owner permissions
!defined('S_IRUSR') && define('S_IRUSR', 00400); //  owner: read permission
!defined('S_IWUSR') && define('S_IWUSR', 00200); //  owner: write permission
!defined('S_IXUSR') && define('S_IXUSR', 00100); //  owner: execute permission
!defined('S_IRWXG') && define('S_IRWXG', 00070); //  mask for group permissions
!defined('S_IRGRP') && define('S_IRGRP', 00040); //  group: read permission
!defined('S_IWGRP') && define('S_IWGRP', 00020); //  group: write permission
!defined('S_IXGRP') && define('S_IXGRP', 00010); //  group: execute permission
!defined('S_IRWXO') && define('S_IRWXO', 00007); //  mask for others permissions
!defined('S_IROTH') && define('S_IROTH', 00004); //  others:  read permission
!defined('S_IWOTH') && define('S_IWOTH', 00002); //  others:  write permission
!defined('S_IXOTH') && define('S_IXOTH', 00001); //  others:  execute permission
 
!defined('S_IRWXUGO') && define('S_IRWXUGO', (S_IRWXU | S_IRWXG | S_IRWXO));
!defined('S_IALLUGO') && define('S_IALLUGO', (S_ISUID | S_ISGID | S_ISVTX | S_IRWXUGO));
!defined('S_IRUGO') && define('S_IRUGO', (S_IRUSR | S_IRGRP | S_IROTH));
!defined('S_IWUGO') && define('S_IWUGO', (S_IWUSR | S_IWGRP | S_IWOTH));
!defined('S_IXUGO') && define('S_IXUGO', (S_IXUSR | S_IXGRP | S_IXOTH));
!defined('S_IRWUGO') && define('S_IRWUGO', (S_IRUGO | S_IWUGO));

How File Permissions Work

When PHP is installed on your server by you or whoever runs the server, it uses the file permissions that are used by the Operating System running the server.. If you are smart or just lucky than you are running some type of BSD/Unix/Solaris/Linux/Sun based Operating system and PHP won't have any problems. If you are running on a Locked, proprietary OS like Windows, PHP will still work but it has to use a lot of shortcuts and hacks to basically "Pretend" to act like the OS is BSD/Unix, and some key features just won't be available.

The OS Permission Bits

Here's the file permissions my Linux server uses, and which PHP automatically uses. The code basically just defines the default permissions for files, and defines the file atributes for each file that you can access by using the stat function, which I've improved upon to make things easier.

Download: POSIX Standard: 5.6 File Characteristicssys/stat.h

Protection bits for File Owner

#define S_IRWXU 00700
#define S_IRUSR 00400
#define S_IWUSR 00200
#define S_IXUSR 00100

Protection bits for File Group

#define S_IRWXG 00070
#define S_IRGRP 00040
#define S_IWGRP 00020
#define S_IXGRP 00010

Protection bits for All Others

#define S_IRWXO 00007
#define S_IROTH 00004
#define S_IWOTH 00002
#define S_IXOTH 00001

Some Example Permissions

0477 // owner has read only, other and group has rwx 0677 // owner has rw only, other and group has rwx

0444 // all have read only 0666 // all have rw only

0400 // owner has read only, group and others have no permission 0600 // owner has rw only, group and others have no permission

0470 // owner has read only, group has rwx, others have no permission 0407 // owner has read only, other has rwx, group has no permission

0670 // owner has rw only, group has rwx, others have no permission 0607 // owner has rw only, group has no permission and others have rwx

What's a File

A file is not merely its contents, a name, and a file type. A file also has an owner (a user ID), a group (a group ID), permissions (what the owner can do with the file, what people in the group can do, and what everyone else can do), various timestamps, and other information. Collectively, we call these a file's attributes.

Structure of File Mode Bits

The file mode bits have two parts: the file permission bits, which control ordinary access to the file, and special mode bits, which affect only some files.

There are three kinds of permissions that a user can have for a file:

1. permission to read the file. For directories, this means permission to list the contents of the directory.
2. permission to write to (change) the file. For directories, this means permission to create and remove files in the directory.
3. permission to execute the file (run it as a program). For directories, this means permission to access files in the directory.

There are three categories of users who may have different permissions to perform any of the above operations on a file:

1. the file's owner.
2. other users who are in the file's group
3. everyone else.

Files are given an owner and group when they are created. Usually the owner is the current user and the group is the group of the directory the file is in, but this varies with the operating system, the file system the file is created on, and the way the file is created. You can change the owner and group of a file by using the chown and chgrp commands.

In addition to the three sets of three permissions listed above, the file mode bits have three special components, which affect only executable files (programs) and, on most systems, directories:

1. Set the process's effective user ID to that of the file upon execution (called the set-user-ID bit, or sometimes the setuid bit). For directories on a few systems, give files created in the directory the same owner as the directory, no matter who creates them, and set the set-user-ID bit of newly-created subdirectories.
2. Set the process's effective group ID to that of the file upon execution (called the set-group-ID bit, or sometimes the setgid bit). For directories on most systems, give files created in the directory the same group as the directory, no matter what group the user who creates them is in, and set the set-group-ID bit of newly-created subdirectories.
3. Prevent unprivileged users from removing or renaming a file in a directory unless they own the file or the directory; this is called the restricted deletion flag for the directory, and is commonly found on world-writable directories like /tmp.

For regular files on some older systems, save the program's text image on the swap device so it will load more quickly when run; this is called the sticky bit.

Setting Permissions

The basic symbolic operations on a file's permissions are adding, removing, and setting the permission that certain users have to read, write, and execute or search the file. These operations have the following format:

users operation permissions

The spaces between the three parts above are shown for readability only; symbolic modes cannot contain spaces. The users part tells which users' access to the file is changed. It consists of one or more of the following letters (or it can be empty). When more than one of these letters is given, the order that they are in does not matter.

• u - the user who owns the file.
• g - other users who are in the file's group.
• o - all other users.
• a - all users; the same as ugo.

The operation part tells how to change the affected users' access to the file, and is one of the following symbols:

• + - to add the permissions to whatever permissions the users already have for the file.
• - - to remove the permissions from whatever permissions the users already have for the file.
• = - to make the permissions the only permissions that the users have for the file.

The permissions part tells what kind of access to the file should be changed; it is normally zero or more of the following letters. As with the users part, the order does not matter when more than one letter is given. Omitting the permissions part is useful only with the = operation, where it gives the specified users no access at all to the file.

• r - the permission the users have to read the file.
• w - the permission the users have to write to the file.
• x - the permission the users have to execute the file, or search it if it is a directory.

For example, to give everyone permission to read and write a regular file, but not to execute it, use:

a=rw

To remove write permission for all users other than the file's owner, use:

go-w

The above command does not affect the access that the owner of the file has to it, nor does it affect whether other users can read or execute the file.

To give everyone except a file's owner no permission to do anything with that file, use the mode below. Other users could still remove the file, if they have write permission on the directory it is in.

go=

Another way to specify the same thing is:

og-rwx

Copying Existing Permissions

You can base a file's permissions on its existing permissions. To do this, instead of using a series of r, w, or x letters after the operator, you use the letter u, g, or o. For example, the mode

o+g

adds the permissions for users who are in a file's group to the permissions that other users have for the file. Thus, if the file started out as mode 664 (rw-rw-r--), the above mode would change it to mode 666 (rw-rw-rw-). If the file had started out as mode 741 (rwxr----x), the above mode would change it to mode 745 (rwxr--r-x). The - and = operations work analogously.

Umask and Protection

If the users part of a symbolic mode is omitted, it defaults to a (affect all users), except that any permissions that are set in the system variable umask are not affected. The value of umask can be set using the umask command. Its default value varies from system to system.

Omitting the users part of a symbolic mode is generally not useful with operations other than +. It is useful with + because it allows you to use umask as an easily customizable protection against giving away more permission to files than you intended to. As an example, if umask has the value 2, which removes write permission for users who are not in the file's group, then the mode:

+w

adds permission to write to the file to its owner and to other users who are in the file's group, but not to other users. In contrast, the mode:

a+w

ignores umask, and does give write permission for the file to all users.

Directories, Set-User-ID and Set-Group-ID Bits

On most systems, if a directory's set-group-ID bit is set, newly created subfiles inherit the same group as the directory, and newly created subdirectories inherit the set-group-ID bit of the parent directory. On a few systems, a directory's set-user-ID bit has a similar effect on the ownership of new subfiles and the set-user-ID bits of new subdirectories. These mechanisms let users share files more easily, by lessening the need to use chmod or chown to share new files.

These convenience mechanisms rely on the set-user-ID and set-group-ID bits of directories. If commands like chmod and mkdir routinely cleared these bits on directories, the mechanisms would be less convenient and it would be harder to share files. Therefore, a command like chmod does not affect the set-user-ID or set-group-ID bits of a directory unless the user specifically mentions them in a symbolic mode, or sets them in a numeric mode. For example, on systems that support set-group-ID inheritance:

# These commands leave the set-user-ID and
# set-group-ID bits of the subdirectories alone,
# so that they retain their default values.
mkdir A B C
chmod 755 A
chmod 0755 B
chmod u=rwx,go=rx C
mkdir -m 755 D
mkdir -m 0755 E
mkdir -m u=rwx,go=rx F

If you want to try to set these bits, you must mention them explicitly in the symbolic or numeric modes, e.g.:

# These commands try to set the set-user-ID
# and set-group-ID bits of the subdirectories.
mkdir G H
chmod 6755 G
chmod u=rwx,go=rx,a+s H
mkdir -m 6755 I
mkdir -m u=rwx,go=rx,a+s J

If you want to try to clear these bits, you must mention them explicitly in a symbolic mode, e.g.:

# This command tries to clear the set-user-ID
# and set-group-ID bits of the directory D.
chmod a-s D

Numeric Modes

The permissions granted to the user, to other users in the file's group, and to other users not in the file's group each require three bits, which are represented as one octal digit. The three special mode bits also require one bit each, and they are as a group represented as another octal digit. Here is how the bits are arranged, starting with the lowest valued bit:

Other users not in the file's group:

1 Execute/search
2 Write
4 Read

Other users in the file's group:

10 Execute/search
20 Write
40 Read

The file's owner:

100 Execute/search
200 Write
400 Read

Special mode bits:

1000 Restricted deletion flag or sticky bit
2000 Set group ID on execution
4000 Set user ID on execution

For example, numeric mode 4755 corresponds to symbolic mode u=rwxs,go=rx, and numeric mode 664 corresponds to symbolic mode ug=rw,o=r. Numeric mode 0 corresponds to symbolic mode a=.

Apache's Internal Bits (hex)

#define APR_FPROT_USETID   0x8000 /* Set user id */
#define APR_FPROT_UREAD   0x0400 /* Read by user */
#define APR_FPROT_UWRITE   0x0200 /* Write by user */
#define APR_FPROT_UEXECUTE 0x0100 /* Execute by user */
 
#define APR_FPROT_GSETID   0x4000 /* Set group id */
#define APR_FPROT_GREAD   0x0040 /* Read by group */
#define APR_FPROT_GWRITE   0x0020 /* Write by group */
#define APR_FPROT_GEXECUTE 0x0010 /* Execute by group */
 
#define APR_FPROT_WSTICKY 0x2000 /* Sticky bit */
#define APR_FPROT_WREAD   0x0004 /* Read by others */
#define APR_FPROT_WWRITE 0x0002 /* Write by others */
#define APR_FPROT_WEXECUTE 0x0001 /* Execute by others */
 
#define APR_FPROT_OS_DEFAULT  0x0FFF /* use OS's default permissions */
 
/* additional permission flags for apr_file_copy  and apr_file_append */
#define APR_FPROT_FILE_SOURCE_PERMS 0x1000 /* Copy source file's permissions */

Download: httpd-2.2.10/srclib/apr/file_io/unix/fileacc.c Here's some interesting bitmasking done by Apache that uses the defined bits set earlier by stat.h

apr_unix_perms2mode(perms){
 mode=0;
 if (perms & APR_USETID) mode |= S_ISUID;
 if (perms & APR_UREAD)  mode |= S_IRUSR;
 if (perms & APR_UWRITE) mode |= S_IWUSR;
 if (perms & APR_UEXECUTE) mode |= S_IXUSR;
 
 if (perms & APR_GSETID) mode |= S_ISGID;
 if (perms & APR_GREAD)  mode |= S_IRGRP;
 if (perms & APR_GWRITE) mode |= S_IWGRP;
 if (perms & APR_GEXECUTE) mode |= S_IXGRP;
 
 if (perms & APR_WSTICKY) mode |= S_ISVTX;
 if (perms & APR_WREAD)  mode |= S_IROTH;
 if (perms & APR_WWRITE) mode |= S_IWOTH;
 if (perms & APR_WEXECUTE) mode |= S_IXOTH;
 return mode;
}
 
apr_unix_mode2perms(mode){
 perms = 0;
 if (mode & S_ISUID)perms |= APR_USETID;
 if (mode & S_IRUSR)perms |= APR_UREAD;
 if (mode & S_IWUSR)perms |= APR_UWRITE;
 if (mode & S_IXUSR)perms |= APR_UEXECUTE;
 
 if (mode & S_ISGID)perms |= APR_GSETID;
 if (mode & S_IRGRP)perms |= APR_GREAD;
 if (mode & S_IWGRP)perms |= APR_GWRITE;
 if (mode & S_IXGRP)perms |= APR_GEXECUTE;
 
 if (mode & S_ISVTX)perms |= APR_WSTICKY;
 if (mode & S_IROTH)perms |= APR_WREAD;
 if (mode & S_IWOTH)perms |= APR_WWRITE;
 if (mode & S_IXOTH)perms |= APR_WEXECUTE;
 return perms;
}

umask

umask(int mask){
 arg1;
 int oldumask;
 int arg_count = ZEND_NUM_ARGS();
 oldumask = umask(077);
 
 if (BG(umask) == -1) BG(umask) = oldumask;
 if (arg_count == 0) umask(oldumask);
 
 convert_to_long_ex(arg1);
 umask(Z_LVAL_PP(arg1));
 RETURN_LONG(oldumask);
}

File Attributes

Each file will have attributes based on the type of OS.. Using the stat command you can view them.

Viewing stat results

* %a - Access rights in octal
* %A - Access rights in human readable form
* %b - Number of blocks allocated (see %B)
* %B - The size in bytes of each block reported by %b
* %d - Device number in decimal
* %D - Device number in hex
* %f - Raw mode in hex
* %F - File type
* %g - Group ID of owner
* %G - Group name of owner
* %h - Number of hard links
* %i - Inode number
* %n - File name
* %N - Quoted file name with dereference if symbolic link
* %o - I/O block size
* %s - Total size, in bytes
* %t - Major device type in hex
* %T - Minor device type in hex
* %u - User ID of owner
* %U - User name of owner
* %x - Time of last access
* %X - Time of last access as seconds since Epoch
* %y - Time of last modification
* %Y - Time of last modification as seconds since Epoch
* %z - Time of last change
* %Z - Time of last change as seconds since Epoch

The OS Attribute Bits

These defined values are what allows your operating system to determine the type of file being accessed.

#define S_IFMT   00170000  /* These bits determine file type. */
#define S_IFSOCK 0140000  /* Socket file */
#define S_IFLNK   0120000  /* Symbolic Link */
#define S_IFREG   0100000  /* Regular file */
#define S_IFDIR   0040000  /* Directory */
#define S_IFIFO  0010000   /* FIFO first-in-first-out file */
 
/* Such devices can be read either a character at a time or a "block" (many characters) at a time,
hence we say there are block special files and character special files. */
#define S_IFBLK   0060000  /* Block device */
#define S_IFCHR  0020000  /* Character device */

Special Permission Bits

#define S_ISUID  0004000  /* Set user ID on execution.  */
#define S_ISGID  0002000  /* Set group ID on execution.  */
#define S_ISVTX  0001000 /* Save swapped text after use (sticky).  */

Bitmasking to determine Filetype

#define S_ISLNK(m) (((m) & S_IFMT) == S_IFLNK)
#define S_ISREG(m) (((m) & S_IFMT) == S_IFREG)
#define S_ISDIR(m) (((m) & S_IFMT) == S_IFDIR)
#define S_ISCHR(m) (((m) & S_IFMT) == S_IFCHR)
#define S_ISBLK(m) (((m) & S_IFMT) == S_IFBLK)
#define S_ISFIFO(m) (((m) & S_IFMT) == S_IFIFO)
#define S_ISSOCK(m) (((m) & S_IFMT) == S_IFSOCK)

Default Permission Masks

#define S_IRWXUGO (S_IRWXU|S_IRWXG|S_IRWXO)
#define S_IALLUGO (S_ISUID|S_ISGID|S_ISVTX|S_IRWXUGO)
#define S_IRUGO  (S_IRUSR|S_IRGRP|S_IROTH)
#define S_IWUGO  (S_IWUSR|S_IWGRP|S_IWOTH)
#define S_IXUGO  (S_IXUSR|S_IXGRP|S_IXOTH)

Download: httpd-2.2.10/srclib/apr/file_io/unix/filestat.c, this file shows a simple way to determine the type of file.

filetype_from_mode(mode){
 type;
 switch (mode & S_IFMT) {
  case S_IFREG:  type = APR_REG;  break;
  case S_IFDIR:  type = APR_DIR;  break;
  case S_IFLNK:  type = APR_LNK;  break;
 
  case S_IFCHR:  type = APR_CHR;  break;
  case S_IFBLK:  type = APR_BLK;  break;
  case S_IFFIFO: type = APR_PIPE; break;
  case S_IFSOCK: type = APR_SOCK; break;
  default: type = APR_UNKFILE;
 }
 return type;
}

Apache Stat Bits

#define APR_FINFO_LINK  0x00000001 /* Stat the link not the file itself if it is a link */
#define APR_FINFO_MTIME  0x00000010 /* Modification Time */
#define APR_FINFO_CTIME  0x00000020 /* Creation or inode-changed time */
#define APR_FINFO_ATIME  0x00000040 /* Access Time */
#define APR_FINFO_SIZE  0x00000100 /* Size of the file */
#define APR_FINFO_CSIZE  0x00000200 /* Storage size consumed by the file */
#define APR_FINFO_DEV  0x00001000 /* Device */
#define APR_FINFO_INODE  0x00002000 /* Inode */
#define APR_FINFO_NLINK  0x00004000 /* Number of links */
#define APR_FINFO_TYPE  0x00008000 /* Type */
#define APR_FINFO_USER  0x00010000 /* User */
#define APR_FINFO_GROUP  0x00020000 /* Group */
#define APR_FINFO_UPROT  0x00100000 /* User protection bits */
#define APR_FINFO_GPROT  0x00200000 /* Group protection bits */
#define APR_FINFO_WPROT  0x00400000 /* World protection bits */
#define APR_FINFO_ICASE  0x01000000 /* if dev is case insensitive */
#define APR_FINFO_NAME  0x02000000 /* name in proper case */
#define APR_FINFO_MIN  0x00008170 /* type, mtime, ctime, atime, size */
#define APR_FINFO_IDENT  0x00003000 /* dev and inode */
#define APR_FINFO_OWNER  0x00030000 /* user and group */
#define APR_FINFO_PROT  0x00700000 /* all protections */
#define APR_FINFO_NORM  0x0073b170 /* an atomic unix apr_stat() */
#define APR_FINFO_DIRENT 0x02000000 /* an atomic unix apr_dir_read() */

The Apache file information structure.

apr_uid_t user;  /* The user id that owns the file */
apr_gid_t group;  /* The group id that owns the file */
apr_ino_t inode; /* The inode of the file. */
apr_dev_t device; /* The id of the device the file is on. */
apr_int32_t nlink; /* The number of hard links to the file. */
apr_off_t size;  /* The size of the file */
apr_off_t csize; /* The storage size consumed by the file */
apr_time_t atime; /* The time the file was last accessed */
apr_time_t mtime; /* The time the file was last modified */
apr_time_t ctime; /* The time the file was created, or the inode was last changed */
const char *fname; /* The pathname of the file (possibly unrooted) */
const char *name; /* The file's name (no path) in filesystem case */

File Time Attributes

touch

If changing both the access and modification times to the current time, touch can change the timestamps for files that the user running it does not own but has write permission for. Otherwise, the user must own the files.

Although touch provides options for changing two of the times the times of last access and modification of a file, there is actually a third one as well: the inode change time. This is often referred to as a file's ctime. The inode change time represents the time when the file's meta-information last changed. One common example of this is when the permissions of a file change. Changing the permissions doesn't access the file, so the atime doesn't change, nor does it modify the file, so the mtime doesn't change. Yet, something about the file itself has changed, and this must be noted somewhere. This is the job of the ctime field. This is necessary, so that, for example, a backup program can make a fresh copy of the file, including the new permissions value. Another operation that modifies a file's ctime without affecting the others is renaming. In any case, it is not possible, in normal operations, for a user to change the ctime field to a user-specified value.

Shared hosting user security

• Shared hosting user security
• Apache Security
• Multiuser security setup example
• SSH key fingerprints
• External Links

WebHost allows you to create multiple users per account. Each user can have domain assigned to its home home directory accessible via FTP or SSH/SCP. The problem with multiple users on the same account is that they share the same default unix group, and default permissions allow their files to be easily modified by the members of this group. Usually this doesn't pose a problem as each user is probably trusted by account owner to not to mess with others files, but if one of the users have their web application hacked then all other users on the same account will be in danger.

By default all files in your account are created with 644 privileges and directories are with 775. That means any user can read your files and any user from the same account can move and add files in your freshly made directories. Your home directory is different, though. By default it carries 751 attribute meaning that only members of your group can see your files, but can't add any new. These group access schemes are possible, because every user in your account has its primary/default group set to "pgxxxxxx", which is assigned to every new file you create by default. The normal way to secure users from web-intrusion is to assign a separate group to the web-server user, removing it from default group. This way, exploited scripts will not be able to traverse into home directories of other users on your account. To allow account users to update centralized web-site they could be added to web-site group explicitly. But this "normal way" doesn't work with DreamHost, because you can't delete web-user from the default group and unless you set access for every new file explicitly, it will be possible for an intruder to read it.

To make managing privileges easier in interactive sessions "umask 007" command can be specified in your .bash_profile - this makes all new files carry xx0 mask. You also need to control your scripts (web based or cron/shell) so that they set mask for critical files explicitly. To secure account users from access by means of hacked user script you would also like to define another group for every user in your account and change group ownership of the user's home directory to that group with "set gid" bit set (and optional umask 007 in .bash_profile).

Therefore, to secure your users from web-intrusion you need to:

1. Add a separate user and group for every domain where apache will be running
2. Add a separate group for other user accounts
3. Change the default group for new files created by your users by changing the group of their home directory and setting "set gid" bit for it (it is impossible to do this with FTP accounts, therefore you will need to login in each account via SSH)
4. Add users who need access to web-site into the web-user group
5. Optionally set umask 007 in .bash_profile for every user to tweak default WebHost775/664 permissions to something like 770/660 for directories and files that are not meant to be read by Apache (660 could also be used for all web scripts including .php as they are not read by dhapache CGI, but merely executed)

Apache Security

All your web files that need to be read by Apache should be readable by everyone as Apache itself is run under dhapache user. However, executable scripts like .php are executed under your own user and do not have to be world readable as they are not actually read by Apache, but executed via suEXEC. Quite the opposite - to prevent your code or database settings from being messed by any third-parties you SHOULD set permissions to these files explicitly to something like 640 or even 600 depending on who do you trust.

Multiuser security setup example

For our example, we will create a rainforce_www user and a aapp_www group for serving web files with apache and setup a rainforce user with a 'aapp group to manage mail and keep other files on DH privately. Since these records already exist, you will need to subsitute your own names.

• Login to create the users rainforce_www and rainforce with shell access.
• Create two groups - aapp_www and aapp. Note that users created in previous step are still members of the same default pgxxxxxx group.
• Add rainforce_www to 'the 'aapp_www group and rainforce to both the aapp_www and aapp groups
• Move your domain to rainforce_www account (mine is rainforce.org)
• Now login to SSH with your rainforce_www user and change the default group for your home directory with "sgid" bit set to make all current and new files/directories created in this directory have the same aapp_www group.

 $ chgrp -R aapp_www .
 $ chmod 2751 .
 $ chmod 2771 rainforce.org

By setting 2771 the directory will be writable by the owner, the group and will be only executable by others. The contents of an executable only directory cannot be listed, but the files inside it can be read (if the permissions of the file allow it). It is important that the directory can be executable in order to allow static content (e.g. .html files) inside it to be read. Remember that directories you don't want anyone to have web access to, should be 0770 (writable by the owner and group, or 0750 writable by the owner and readable by group). Such strict permissions should by applied to password files, php include files or databases files (such as SQLite, BDB, etc).

• Do the same for rainforce user, but specify aapp group instead.

 $ chgrp -R aapp .
 $ chmod 2751 .

• Optionally modify umask in .bash_profile in user's home to 007 to make all files created by this user have 660 permissions set by default. If you want that newly created files by accessible by the web, you need to manually setup it's permissions to 664.

Now I can login as the user "rainforce" and update the web-site in the ../rainforce_www/rainforce.org directory. There is one more setup needed. Because files copied from other accounts can have 644 permissions set instead of 664, you need a script which will update permissions to 664 or 660 to allow other group members modify such files.

SSH key fingerprints

Just gen your own I guess

External Links

• Introduction to Unix file permissions
• Understanding UNIX permission and chmod

Original Article from DreamHost Wiki

Content is available under GNU Free Documentation License 1.2.

Example File Permission Bits

/usr/lib/w3m/cgi-bin/dirlist.cgi

sub utype {
  local($_) = @_;
  local(%T) = (
    0010000, 'PIPE',
    0020000, 'CHR',
    0040000, 'DIR',
    0060000, 'BLK',
    0100000, 'FILE',
    0120000, 'LINK',
    0140000, 'SOCK',
  );
  return $T{($_ & 0170000)} || 'FILE';
}
 
sub umode {
  local($_) = @_;
  local(%T) = (
    0010000, 'p',
    0020000, 'c',
    0040000, 'd',
    0060000, 'b',
    0100000, '-',
    0120000, 'l',
    0140000, 's',
  );
 
  return ($T{($_ & 0170000)} || '-')
     . (($_ & 00400) ? 'r' : '-')
     . (($_ & 00200) ? 'w' : '-')
     . (($_ & 04000) ? 's' :
       (($_ & 00100) ? 'x' : '-'))
     . (($_ & 00040) ? 'r' : '-')
     . (($_ & 00020) ? 'w' : '-')
     . (($_ & 02000) ? 's' :
       (($_ & 00010) ? 'x' : '-'))
     . (($_ & 00004) ? 'r' : '-')
     . (($_ & 00002) ? 'w' : '-')
     . (($_ & 01000) ? 't' :
       (($_ & 00001) ? 'x' : '-'));
}

/usr/lib/perl/5.8.4/linux/stat.ph

        eval 'sub S_IFMT () {00170000;}' unless defined(&S_IFMT);
        eval 'sub S_IFSOCK () {0140000;}' unless defined(&S_IFSOCK);
        eval 'sub S_IFLNK () {0120000;}' unless defined(&S_IFLNK);
        eval 'sub S_IFREG () {0100000;}' unless defined(&S_IFREG);
        eval 'sub S_IFBLK () {0060000;}' unless defined(&S_IFBLK);
        eval 'sub S_IFDIR () {0040000;}' unless defined(&S_IFDIR);
        eval 'sub S_IFCHR () {0020000;}' unless defined(&S_IFCHR);
        eval 'sub S_IFIFO () {0010000;}' unless defined(&S_IFIFO);
        eval 'sub S_ISUID () {0004000;}' unless defined(&S_ISUID);
        eval 'sub S_ISGID () {0002000;}' unless defined(&S_ISGID);
        eval 'sub S_ISVTX () {0001000;}' unless defined(&S_ISVTX);
        eval 'sub S_ISLNK {
            local($m) = @_;
            eval q(((($m) &  &S_IFMT) ==  &S_IFLNK));
        }' unless defined(&S_ISLNK);
        eval 'sub S_ISREG {
            local($m) = @_;
            eval q(((($m) &  &S_IFMT) ==  &S_IFREG));
        }' unless defined(&S_ISREG);
        eval 'sub S_ISDIR {
            local($m) = @_;
            eval q(((($m) &  &S_IFMT) ==  &S_IFDIR));
        }' unless defined(&S_ISDIR);
        eval 'sub S_ISCHR {
            local($m) = @_;
            eval q(((($m) &  &S_IFMT) ==  &S_IFCHR));
        }' unless defined(&S_ISCHR);
        eval 'sub S_ISBLK {
            local($m) = @_;
            eval q(((($m) &  &S_IFMT) ==  &S_IFBLK));
        }' unless defined(&S_ISBLK);
        eval 'sub S_ISFIFO {
            local($m) = @_;
            eval q(((($m) &  &S_IFMT) ==  &S_IFIFO));
        }' unless defined(&S_ISFIFO);
        eval 'sub S_ISSOCK {
            local($m) = @_;
            eval q(((($m) &  &S_IFMT) ==  &S_IFSOCK));
        }' unless defined(&S_ISSOCK);
        eval 'sub S_IRWXU () {00700;}' unless defined(&S_IRWXU);
        eval 'sub S_IRUSR () {00400;}' unless defined(&S_IRUSR);
        eval 'sub S_IWUSR () {00200;}' unless defined(&S_IWUSR);
        eval 'sub S_IXUSR () {00100;}' unless defined(&S_IXUSR);
        eval 'sub S_IRWXG () {00070;}' unless defined(&S_IRWXG);
        eval 'sub S_IRGRP () {00040;}' unless defined(&S_IRGRP);
        eval 'sub S_IWGRP () {00020;}' unless defined(&S_IWGRP);
        eval 'sub S_IXGRP () {00010;}' unless defined(&S_IXGRP);
        eval 'sub S_IRWXO () {00007;}' unless defined(&S_IRWXO);
        eval 'sub S_IROTH () {00004;}' unless defined(&S_IROTH);
        eval 'sub S_IWOTH () {00002;}' unless defined(&S_IWOTH);
        eval 'sub S_IXOTH () {00001;}' unless defined(&S_IXOTH);
    }
    if(defined(&__KERNEL__)) {
        eval 'sub S_IRWXUGO () {( &S_IRWXU| &S_IRWXG| &S_IRWXO);}' unless defined(&S_IRWXUGO);
        eval 'sub S_IALLUGO () {( &S_ISUID| &S_ISGID| &S_ISVTX| &S_IRWXUGO);}' unless defined(&S_IALLUGO);
        eval 'sub S_IRUGO () {( &S_IRUSR| &S_IRGRP| &S_IROTH);}' unless defined(&S_IRUGO);
        eval 'sub S_IWUGO () {( &S_IWUSR| &S_IWGRP| &S_IWOTH);}' unless defined(&S_IWUGO);
        eval 'sub S_IXUGO () {( &S_IXUSR| &S_IXGRP| &S_IXOTH);}' unless defined(&S_IXUGO);
        require 'linux/types.ph';
        require 'linux/time.ph';
    }
 

Mozilla-Source 1.8a2

/* notice that these valuse are octal. */
const PERM_IRWXU = 00700;  /* read, write, execute/search by owner */
const PERM_IRUSR = 00400;  /* read permission, owner */
const PERM_IWUSR = 00200;  /* write permission, owner */
const PERM_IXUSR = 00100;  /* execute/search permission, owner */
const PERM_IRWXG = 00070;  /* read, write, execute/search by group */
const PERM_IRGRP = 00040;  /* read permission, group */
const PERM_IWGRP = 00020;  /* write permission, group */
const PERM_IXGRP = 00010;  /* execute/search permission, group */
const PERM_IRWXO = 00007;  /* read, write, execute/search by others */
const PERM_IROTH = 00004;  /* read permission, others */
const PERM_IWOTH = 00002;  /* write permission, others */
const PERM_IXOTH = 00001;  /* execute/search permission, others */
 
const MODE_RDONLY   = 0x01;
const MODE_WRONLY   = 0x02;
const MODE_RDWR     = 0x04;
const MODE_CREATE   = 0x08;
const MODE_APPEND   = 0x10;
const MODE_TRUNCATE = 0x20;
const MODE_SYNC     = 0x40;
const MODE_EXCL     = 0x80;

/usr/include/libpng12/png.h

/* Transform masks for the high-level interface */
#define PNG_TRANSFORM_IDENTITY       0x0000    /* read and write */
#define PNG_TRANSFORM_STRIP_16       0x0001    /* read only */
#define PNG_TRANSFORM_STRIP_ALPHA    0x0002    /* read only */
#define PNG_TRANSFORM_PACKING        0x0004    /* read and write */
#define PNG_TRANSFORM_PACKSWAP       0x0008    /* read and write */
#define PNG_TRANSFORM_EXPAND         0x0010    /* read only */
#define PNG_TRANSFORM_INVERT_MONO    0x0020    /* read and write */
#define PNG_TRANSFORM_SHIFT          0x0040    /* read and write */
#define PNG_TRANSFORM_BGR            0x0080    /* read and write */
#define PNG_TRANSFORM_SWAP_ALPHA     0x0100    /* read and write */
#define PNG_TRANSFORM_SWAP_ENDIAN    0x0200    /* read and write */
#define PNG_TRANSFORM_INVERT_ALPHA   0x0400    /* read and write */
#define PNG_TRANSFORM_STRIP_FILLER   0x0800    /* WRITE only */

/usr/lib/python2.4/stat.py

# Extract bits from the mode
 
def S_IMODE(mode):
    return mode & 07777
 
def S_IFMT(mode):
    return mode & 0170000
 
# Constants used as S_IFMT() for various file types
# (not all are implemented on all systems)
 
S_IFDIR  = 0040000
S_IFCHR  = 0020000
S_IFBLK  = 0060000
S_IFREG  = 0100000
S_IFIFO  = 0010000
S_IFLNK  = 0120000
S_IFSOCK = 0140000
 
# Functions to test for each file type
 
def S_ISDIR(mode):
    return S_IFMT(mode) == S_IFDIR
 
def S_ISCHR(mode):
    return S_IFMT(mode) == S_IFCHR
 
def S_ISBLK(mode):
    return S_IFMT(mode) == S_IFBLK
 
def S_ISREG(mode):
    return S_IFMT(mode) == S_IFREG
 
def S_ISFIFO(mode):
    return S_IFMT(mode) == S_IFIFO
 
def S_ISLNK(mode):
    return S_IFMT(mode) == S_IFLNK
 
def S_ISSOCK(mode):
    return S_IFMT(mode) == S_IFSOCK
 
# Names for permission bits
 
S_ISUID = 04000
S_ISGID = 02000
S_ENFMT = S_ISGID
S_ISVTX = 01000
S_IREAD = 00400
S_IWRITE = 00200
S_IEXEC = 00100
S_IRWXU = 00700
S_IRUSR = 00400
S_IWUSR = 00200
S_IXUSR = 00100
S_IRWXG = 00070
S_IRGRP = 00040
S_IWGRP = 00020
S_IXGRP = 00010
S_IRWXO = 00007
S_IROTH = 00004
S_IWOTH = 00002
S_IXOTH = 00001

/usr/include/bits/stat.h

/* Encoding of the file mode.  */
 
#define __S_IFMT        0170000 /* These bits determine file type.  */
 
/* File types.  */
#define __S_IFDIR       0040000 /* Directory.  */
#define __S_IFCHR       0020000 /* Character device.  */
#define __S_IFBLK       0060000 /* Block device.  */
#define __S_IFREG       0100000 /* Regular file.  */
#define __S_IFIFO       0010000 /* FIFO.  */
#define __S_IFLNK       0120000 /* Symbolic link.  */
#define __S_IFSOCK      0140000 /* Socket.  */
 
/* POSIX.1b objects.  Note that these macros always evaluate to zero.  But
   they do it by enforcing the correct use of the macros.  */
#define __S_TYPEISMQ(buf)  ((buf)->st_mode - (buf)->st_mode)
#define __S_TYPEISSEM(buf) ((buf)->st_mode - (buf)->st_mode)
#define __S_TYPEISSHM(buf) ((buf)->st_mode - (buf)->st_mode)
 
/* Protection bits.  */
 
#define __S_ISUID       04000   /* Set user ID on execution.  */
#define __S_ISGID       02000   /* Set group ID on execution.  */
#define __S_ISVTX       01000   /* Save swapped text after use (sticky).  */
#define __S_IREAD       0400    /* Read by owner.  */
#define __S_IWRITE      0200    /* Write by owner.  */
#define __S_IEXEC       0100    /* Execute by owner.  */

/usr/include/linux/nfs.h

#define NFS_FIFO_DEV    (-1)
#define NFSMODE_FMT     0170000
#define NFSMODE_DIR     0040000
#define NFSMODE_CHR     0020000
#define NFSMODE_BLK     0060000
#define NFSMODE_REG     0100000
#define NFSMODE_LNK     0120000
#define NFSMODE_SOCK    0140000
#define NFSMODE_FIFO    0010000

/usr/include/linux/nfs3.h

#define NFS3_FIFO_DEV           (-1)
#define NFS3MODE_FMT            0170000
#define NFS3MODE_DIR            0040000
#define NFS3MODE_CHR            0020000
#define NFS3MODE_BLK            0060000
#define NFS3MODE_REG            0100000
#define NFS3MODE_LNK            0120000
#define NFS3MODE_SOCK           0140000
#define NFS3MODE_FIFO           0010000
 
/* Flags for access() call */
#define NFS3_ACCESS_READ        0x0001
#define NFS3_ACCESS_LOOKUP      0x0002
#define NFS3_ACCESS_MODIFY      0x0004
#define NFS3_ACCESS_EXTEND      0x0008
#define NFS3_ACCESS_DELETE      0x0010
#define NFS3_ACCESS_EXECUTE     0x0020
#define NFS3_ACCESS_FULL        0x003f

/usr/include/linux/stat.h

#define S_IFMT  00170000
#define S_IFSOCK 0140000
#define S_IFLNK  0120000
#define S_IFREG  0100000
#define S_IFBLK  0060000
#define S_IFDIR  0040000
#define S_IFCHR  0020000
#define S_IFIFO  0010000
#define S_ISUID  0004000
#define S_ISGID  0002000
#define S_ISVTX  0001000
 
#define S_ISLNK(m)      (((m) & S_IFMT) == S_IFLNK)
#define S_ISREG(m)      (((m) & S_IFMT) == S_IFREG)
#define S_ISDIR(m)      (((m) & S_IFMT) == S_IFDIR)
#define S_ISCHR(m)      (((m) & S_IFMT) == S_IFCHR)
#define S_ISBLK(m)      (((m) & S_IFMT) == S_IFBLK)
#define S_ISFIFO(m)     (((m) & S_IFMT) == S_IFIFO)
#define S_ISSOCK(m)     (((m) & S_IFMT) == S_IFSOCK)
 
#define S_IRWXU 00700
#define S_IRUSR 00400
#define S_IWUSR 00200
#define S_IXUSR 00100
 
#define S_IRWXG 00070
#define S_IRGRP 00040
#define S_IWGRP 00020
#define S_IXGRP 00010
 
#define S_IRWXO 00007
#define S_IROTH 00004
#define S_IWOTH 00002
#define S_IXOTH 00001

Further File Permissions Reading

Related PHP Functions

• fileperms
• stat
• chmod
• clearstatcache
• chown
• chgrp
• lchown
• lchgrp
• touch
• lstat
• filestat
• fileatime
• filectime
• filegroup
• fileinode
• filemtime
• fileowner
• filesize
• filetype
• is_writable
• is_readable
• is_executable
• is_file
• is_dir
• is_link
• file_exists
• disk_total_space
• disk_free_space

Special file types

• link invocation: Make a hard link via the link syscall
• ln invocation: Make links between files
• mkdir invocation: Make directories
• mkfifo invocation: Make FIFOs (named pipes)
• mknod invocation: Make block or character special files
• readlink invocation: Print the referent of a symbolic link
• rmdir invocation: Remove empty directories
• unlink invocation: Remove files via unlink syscall

Changing file attributes

• chown invocation: Change file owner and group
• chgrp invocation: Change group ownership
• chmod invocation: Change access permissions
• touch invocation: Change file timestamps

Chmod, Umask, Stat, Fileperms, and File Permissions originally appeared on AskApache.com

HTTP Headers

9 Method Definitions

The set of common methods for HTTP/1.1 is defined below. Although this set can be expanded, additional methods cannot be assumed to share the same semantics for separately extended clients and servers.

The Host request-header field (section 14.23) MUST accompany all HTTP/1.1 requests.

9.1 Safe and Idempotent Methods

9.1.1 Safe Methods

Implementors should be aware that the software represents the user in their interactions over the Internet, and should be careful to allow the user to be aware of any actions they might take which may have an unexpected significance to themselves or others.

In particular, the convention has been established that the GET and HEAD methods SHOULD NOT have the significance of taking an action other than retrieval. These methods ought to be considered "safe". This allows user agents to represent other methods, such as POST, PUT and DELETE, in a special way, so that the user is made aware of the fact that a possibly unsafe action is being requested.

Naturally, it is not possible to ensure that the server does not generate side-effects as a result of performing a GET request; in fact, some dynamic resources consider that a feature. The important distinction here is that the user did not request the side-effects, so therefore cannot be held accountable for them.

9.1.2 Idempotent Methods

Methods can also have the property of "idempotence" in that (aside from error or expiration issues) the side-effects of N > 0 identical requests is the same as for a single request. The methods GET, HEAD, PUT and DELETE share this property. Also, the methods OPTIONS and TRACE SHOULD NOT have side effects, and so are inherently idempotent.

However, it is possible that a sequence of several requests is non- idempotent, even if all of the methods executed in that sequence are idempotent. (A sequence is idempotent if a single execution of the entire sequence always yields a result that is not changed by a reexecution of all, or part, of that sequence.) For example, a sequence is non-idempotent if its result depends on a value that is later modified in the same sequence.

A sequence that never has side effects is idempotent, by definition (provided that no concurrent operations are being executed on the same set of resources).

9.2 OPTIONS

The OPTIONS method represents a request for information about the communication options available on the request/response chain identified by the Request-URI. This method allows the client to determine the options and/or requirements associated with a resource, or the capabilities of a server, without implying a resource action or initiating a resource retrieval.

Responses to this method are not cacheable.

If the OPTIONS request includes an entity-body (as indicated by the presence of Content-Length or Transfer-Encoding), then the media type MUST be indicated by a Content-Type field. Although this specification does not define any use for such a body, future extensions to HTTP might use the OPTIONS body to make more detailed queries on the server. A server that does not support such an extension MAY discard the request body.

If the Request-URI is an asterisk ("*"), the OPTIONS request is intended to apply to the server in general rather than to a specific resource. Since a server's communication options typically depend on the resource, the "*" request is only useful as a "ping" or "no-op" type of method; it does nothing beyond allowing the client to test the capabilities of the server. For example, this can be used to test a proxy for HTTP/1.1 compliance (or lack thereof).

If the Request-URI is not an asterisk, the OPTIONS request applies only to the options that are available when communicating with that resource.

A 200 response SHOULD include any header fields that indicate optional features implemented by the server and applicable to that resource (e.g., Allow), possibly including extensions not defined by this specification. The response body, if any, SHOULD also include information about the communication options. The format for such a

body is not defined by this specification, but might be defined by future extensions to HTTP. Content negotiation MAY be used to select the appropriate response format. If no response body is included, the response MUST include a Content-Length field with a field-value of "0".

The Max-Forwards request-header field MAY be used to target a specific proxy in the request chain. When a proxy receives an OPTIONS request on an absoluteURI for which request forwarding is permitted, the proxy MUST check for a Max-Forwards field. If the Max-Forwards field-value is zero ("0"), the proxy MUST NOT forward the message; instead, the proxy SHOULD respond with its own communication options. If the Max-Forwards field-value is an integer greater than zero, the proxy MUST decrement the field-value when it forwards the request. If no Max-Forwards field is present in the request, then the forwarded request MUST NOT include a Max-Forwards field.

9.3 GET

The GET method means retrieve whatever information (in the form of an entity) is identified by the Request-URI. If the Request-URI refers to a data-producing process, it is the produced data which shall be returned as the entity in the response and not the source text of the process, unless that text happens to be the output of the process.

The semantics of the GET method change to a "conditional GET" if the request message includes an If-Modified-Since, If-Unmodified-Since, If-Match, If-None-Match, or If-Range header field. A conditional GET method requests that the entity be transferred only under the circumstances described by the conditional header field(s). The conditional GET method is intended to reduce unnecessary network usage by allowing cached entities to be refreshed without requiring multiple requests or transferring data already held by the client.

The semantics of the GET method change to a "partial GET" if the request message includes a Range header field. A partial GET requests that only part of the entity be transferred, as described in section 14.35. The partial GET method is intended to reduce unnecessary network usage by allowing partially-retrieved entities to be completed without transferring data already held by the client.

The response to a GET request is cacheable if and only if it meets the requirements for HTTP caching described in section 13.

See section 15.1.3 for security considerations when used for forms.

9.4 HEAD

The HEAD method is identical to GET except that the server MUST NOT return a message-body in the response. The metainformation contained in the HTTP headers in response to a HEAD request SHOULD be identical to the information sent in response to a GET request. This method can be used for obtaining metainformation about the entity implied by the request without transferring the entity-body itself. This method is often used for testing hypertext links for validity, accessibility, and recent modification.

The response to a HEAD request MAY be cacheable in the sense that the information contained in the response MAY be used to update a previously cached entity from that resource. If the new field values indicate that the cached entity differs from the current entity (as would be indicated by a change in Content-Length, Content-MD5, ETag or Last-Modified), then the cache MUST treat the cache entry as stale.

9.5 POST

The POST method is used to request that the origin server accept the entity enclosed in the request as a new subordinate of the resource identified by the Request-URI in the Request-Line. POST is designed to allow a uniform method to cover the following functions:

      - Annotation of existing resources; 

      - Posting a message to a bulletin board, newsgroup, mailing list, or similar group of articles; 

      - Providing a block of data, such as the result of submitting a form, to a data-handling process; 

      - Extending a database through an append operation. 

The actual function performed by the POST method is determined by the server and is usually dependent on the Request-URI. The posted entity is subordinate to that URI in the same way that a file is subordinate to a directory containing it, a news article is subordinate to a newsgroup to which it is posted, or a record is subordinate to a database.

The action performed by the POST method might not result in a resource that can be identified by a URI. In this case, either 200 (OK) or 204 (No Content) is the appropriate response status, depending on whether or not the response includes an entity that describes the result.

If a resource has been created on the origin server, the response SHOULD be 201 (Created) and contain an entity which describes the status of the request and refers to the new resource, and a Location header (see section 14.30).

Responses to this method are not cacheable, unless the response includes appropriate Cache-Control or Expires header fields. However, the 303 (See Other) response can be used to direct the user agent to retrieve a cacheable resource.

POST requests MUST obey the message transmission requirements set out in section 8.2.

See section 15.1.3 for security considerations.

9.6 PUT

The PUT method requests that the enclosed entity be stored under the supplied Request-URI. If the Request-URI refers to an already existing resource, the enclosed entity SHOULD be considered as a modified version of the one residing on the origin server. If the Request-URI does not point to an existing resource, and that URI is capable of being defined as a new resource by the requesting user agent, the origin server can create the resource with that URI. If a new resource is created, the origin server MUST inform the user agent via the 201 (Created) response. If an existing resource is modified, either the 200 (OK) or 204 (No Content) response codes SHOULD be sent to indicate successful completion of the request. If the resource could not be created or modified with the Request-URI, an appropriate error response SHOULD be given that reflects the nature of the problem. The recipient of the entity MUST NOT ignore any Content-* (e.g. Content-Range) headers that it does not understand or implement and MUST return a 501 (Not Implemented) response in such cases.

If the request passes through a cache and the Request-URI identifies one or more currently cached entities, those entries SHOULD be treated as stale. Responses to this method are not cacheable.

The fundamental difference between the POST and PUT requests is reflected in the different meaning of the Request-URI. The URI in a POST request identifies the resource that will handle the enclosed entity. That resource might be a data-accepting process, a gateway to some other protocol, or a separate entity that accepts annotations. In contrast, the URI in a PUT request identifies the entity enclosed with the request -- the user agent knows what URI is intended and the server MUST NOT attempt to apply the request to some other resource. If the server desires that the request be applied to a different URI,

it MUST send a 301 (Moved Permanently) response; the user agent MAY then make its own decision regarding whether or not to redirect the request.

A single resource MAY be identified by many different URIs. For example, an article might have a URI for identifying "the current version" which is separate from the URI identifying each particular version. In this case, a PUT request on a general URI might result in several other URIs being defined by the origin server.

HTTP/1.1 does not define how a PUT method affects the state of an origin server.

PUT requests MUST obey the message transmission requirements set out in section 8.2.

Unless otherwise specified for a particular entity-header, the entity-headers in the PUT request SHOULD be applied to the resource created or modified by the PUT.

9.7 DELETE

The DELETE method requests that the origin server delete the resource identified by the Request-URI. This method MAY be overridden by human intervention (or other means) on the origin server. The client cannot be guaranteed that the operation has been carried out, even if the status code returned from the origin server indicates that the action has been completed successfully. However, the server SHOULD NOT indicate success unless, at the time the response is given, it intends to delete the resource or move it to an inaccessible location.

A successful response SHOULD be 200 (OK) if the response includes an entity describing the status, 202 (Accepted) if the action has not yet been enacted, or 204 (No Content) if the action has been enacted but the response does not include an entity.

If the request passes through a cache and the Request-URI identifies one or more currently cached entities, those entries SHOULD be treated as stale. Responses to this method are not cacheable.

9.8 TRACE

The TRACE method is used to invoke a remote, application-layer loop- back of the request message. The final recipient of the request SHOULD reflect the message received back to the client as the entity-body of a 200 (OK) response. The final recipient is either the

origin server or the first proxy or gateway to receive a Max-Forwards value of zero (0) in the request (see section 14.31). A TRACE request MUST NOT include an entity.

TRACE allows the client to see what is being received at the other end of the request chain and use that data for testing or diagnostic information. The value of the Via header field (section 14.45) is of particular interest, since it acts as a trace of the request chain. Use of the Max-Forwards header field allows the client to limit the length of the request chain, which is useful for testing a chain of proxies forwarding messages in an infinite loop.

If the request is valid, the response SHOULD contain the entire request message in the entity-body, with a Content-Type of "message/http". Responses to this method MUST NOT be cached.

9.9 CONNECT

This specification reserves the method name CONNECT for use with a proxy that can dynamically switch to being a tunnel (e.g. SSL tunneling [44]).

List of HTTP Response Status Codes

1xx Info / Informational

HTTP_INFO - Request received, continuing process.

Indicates a provisional response, consisting only of the Status-Line and optional headers, and is terminated by an empty line.

• 100 Continue - HTTP_CONTINUE
• 101 Switching Protocols - HTTP_SWITCHING_PROTOCOLS
• 102 Processing - HTTP_PROCESSING

2xx Success / OK

HTTP_SUCCESS - The action was successfully received, understood, and accepted.

Indicates that the client's request was successfully received, understood, and accepted.

• 200 OK - HTTP_OK
• 201 Created - HTTP_CREATED
• 202 Accepted - HTTP_ACCEPTED
• 203 Non-Authoritative Information - HTTP_NON_AUTHORITATIVE
• 204 No Content - HTTP_NO_CONTENT
• 205 Reset Content - HTTP_RESET_CONTENT
• 206 Partial Content - HTTP_PARTIAL_CONTENT
• 207 Multi-Status - HTTP_MULTI_STATUS

3xx Redirect

HTTP_REDIRECT - The client must take additional action to complete the request.

Indicates that further action needs to be taken by the user-agent in order to fulfill the request. The action required may be carried out by the user agent without interaction with the user if and only if the method used in the second request is GET or HEAD. A user agent should not automatically redirect a request more than 5 times, since such redirections usually indicate an infinite loop.

• 300 Multiple Choices - HTTP_MULTIPLE_CHOICES
• 301 Moved Permanently - HTTP_MOVED_PERMANENTLY
• 302 Found - HTTP_MOVED_TEMPORARILY
• 303 See Other - HTTP_SEE_OTHER
• 304 Not Modified - HTTP_NOT_MODIFIED
• 305 Use Proxy - HTTP_USE_PROXY
• 306 unused - UNUSED
• 307 Temporary Redirect - HTTP_TEMPORARY_REDIRECT

4xx Client Error

HTTP_CLIENT_ERROR - The request contains bad syntax or cannot be fulfilled.

Indicates case where client seems to have erred. Except when responding to a HEAD request, the server should include an entity containing an explanation of the error situation, and whether it is a temporary or permanent condition.

• 400 Bad Request - HTTP_BAD_REQUEST
• 401 Authorization Required - HTTP_UNAUTHORIZED
• 402 Payment Required - HTTP_PAYMENT_REQUIRED
• 403 Forbidden - HTTP_FORBIDDEN
• 404 Not Found - HTTP_NOT_FOUND
• 405 Method Not Allowed - HTTP_METHOD_NOT_ALLOWED
• 406 Not Acceptable - HTTP_NOT_ACCEPTABLE
• 407 Proxy Authentication Required - HTTP_PROXY_AUTHENTICATION_REQUIRED
• 408 Request Time-out - HTTP_REQUEST_TIME_OUT
• 409 Conflict - HTTP_CONFLICT
• 410 Gone - HTTP_GONE
• 411 Length Required - HTTP_LENGTH_REQUIRED
• 412 Precondition Failed - HTTP_PRECONDITION_FAILED
• 413 Request Entity Too Large - HTTP_REQUEST_ENTITY_TOO_LARGE
• 414 Request-URI Too Large - HTTP_REQUEST_URI_TOO_LARGE
• 415 Unsupported Media Type - HTTP_UNSUPPORTED_MEDIA_TYPE
• 416 Requested Range Not Satisfiable - HTTP_RANGE_NOT_SATISFIABLE
• 417 Expectation Failed - HTTP_EXPECTATION_FAILED
• 418 unused - UNUSED
• 419 unused - UNUSED
• 420 unused - UNUSED
• 421 unused - UNUSED
• 422 Unprocessable Entity - HTTP_UNPROCESSABLE_ENTITY
• 423 Locked - HTTP_LOCKED
• 424 Failed Dependency - HTTP_FAILED_DEPENDENCY
• 425 No code - HTTP_NO_CODE
• 426 Upgrade Required - HTTP_UPGRADE_REQUIRED

5xx Server Error

HTTP_SERVER_ERROR - The server failed to fulfill an apparently valid request.

Indicate cases in which the server is aware that it has erred or is incapable of performing the request. Except when responding to a HEAD request, the server should include an entity containing an explanation of the error situation, and whether it is a temporary or permanent condition. User agents should display any included entity to the user. These response codes are applicable to any request method.

• 500 Internal Server Error - HTTP_INTERNAL_SERVER_ERROR
• 501 Method Not Implemented - HTTP_NOT_IMPLEMENTED
• 502 Bad Gateway - HTTP_BAD_GATEWAY
• 503 Service Temporarily Unavailable - HTTP_SERVICE_UNAVAILABLE
• 504 Gateway Time-out - HTTP_GATEWAY_TIME_OUT
• 505 HTTP Version Not Supported - HTTP_VERSION_NOT_SUPPORTED
• 506 Variant Also Negotiates - HTTP_VARIANT_ALSO_VARIES
• 507 Insufficient Storage - HTTP_INSUFFICIENT_STORAGE
• 508 unused - UNUSED
• 509 unused - UNUSED
• 510 Not Extended - HTTP_NOT_EXTENDED

Helpful HTTP Links

1. HTTP specification, Section 10
2. TLS Upgrade within HTTP specification, Section 4
3. HTTP Status Code Registry
4. WebDAV specification, Section 11
5. IANA registry
6. Adobe Flash status code definitions (ie 408)
7. Microsoft Internet Information Server Status Codes and Sub-Codes
8. httplint
9. HTTP Headers, brief intro.
10. Common User-Agent Issues

DRP

"The HTTP Distribution and Replication Protocol"

DupSup

"Duplicate Suppression in HTTP"

EARL Schema

"Evaluation and Report Language (EARL) 1.0 Schema"

EDD

"An exploration of dynamic documents"

EdgeArch

"Edge Architecture Specification"

HttpClient

Jakarta Commons HttpClient

HTML4

"HTML 4.01 Specification"

JEPI

"White Paper: Joint Electronic Payment Initiative"

ObjectHeaders

"Object Header lines in HTTP"

OPS-OverHTTP

"Implementation of OPS Over HTTP"

OPTIONS messages

"Specification of HTTP/1.1 OPTIONS messages"

P3P

"The Platform for Privacy Preferences 1.0 (P3P1.0) Specification"

PEP

"PEP - an Extension Mechanism for HTTP"

PICSLabels

"PICS Label Distribution Label Syntax and Communication Protocols, Version 1.1"

Proxy Notification

"Notification for Proxy Caches"

RDF

"Resource Description Framework (RDF): Concepts and Abstract Syntax"

RDF-PRIMER

RDF Primer

RFC2068

"Hypertext Transfer Protocol -- HTTP/1.1"

RFC2109

"HTTP State Management Mechanism"

RFC2183

"Communicating Presentation Information in Internet Messages: The Content-Disposition Header Field"

RFC2227

"Simple Hit-Metering and Usage-Limiting for HTTP"

RFC2295

"Transparent Content Negotiation in HTTP"

RFC2310

"The Safe Response Header Field"

RFC2324

"Hyper Text Coffee Pot Control Protocol (HTCPCP/1.0)"

RFC2397

"The 'data' URL scheme"

RFC2518

"HTTP Extensions for Distributed Authoring -- WEBDAV"

RFC2616

"Hypertext Transfer Protocol -- HTTP/1.1"

RFC2617

"HTTP Authentication: Basic and Digest Access Authentication"

RFC2660

"The Secure HyperText Transfer Protocol"

RFC2774

"An HTTP Extension Framework"

RFC2965

"HTTP State Management Mechanism"

RFC3229

"Delta encoding in HTTP"

RFC3230

"Instance Digests in HTTP"

RFC3253

"Versioning Extensions to WebDAV (Web Distributed Authoring and Versioning)"

RFC3648

"Web Distributed Authoring and Versioning (WebDAV) Ordered Collections Protocol"

RFC3986

"Uniform Resource Identifier (URI): Generic Syntax"

RFC4229

"HTTP Header Field Registrations"

SOAP1.1

"Simple Object Access Protocol (SOAP) 1.1"

UA Attributes

"User-Agent Display Attributes Headers"

WIRE

"WIRE - W3 Identifier Resolution Extensions"

Raw HTTP Header Debugger originally appeared on AskApache.com

Htaccess Rewrites are enabled by using the Apache module mod_rewrite, which is one of the most powerful Apache modules and features availale. Htaccess Rewrites through mod_rewrite provide the special ability to Rewrite requests internally as well as Redirect request externally.

When the url in your browser's location bar stays the same for a request it is an internal rewrite, when the url changes an external redirection is taking place. This is one of the first, and one of the biggest mental-blocks people have when learning about mod_rewrite... But I have a secret weapon for you to use, a new discovery from years of research that makes learning mod_rewrite drastically quicker and easier. It truly does or I wouldn't be saying so in the introduction of this article.

Despite the tons of examples and docs, mod_rewrite is voodoo. Damned cool voodoo, but still voodoo.
-- Brian Moore

Note: After years of fighting to learn my way through rewriting urls with mod_rewrite, I finally had a breakthrough and found a way to outsmart the difficulty of mod_rewrite that I just couldn't seem to master. The Mod_Rewrite RewriteCond/RewriteRule Variable Value Cheatsheet is the one-of-a-kind tool that changed the game for me and made mod_rewriting no-harder than anything else.

So keep that mod_rewrite reference bookmarked and you will be able to figure out any RewriteRule or RewriteCond, an amazing feat considering it took me a LONG time to figure this stuff out on my own. But that was before the craziness, one of the most challenging and productive .htaccess experiments I've done... An experiment so ILL it's sick like a diamond disease on your wrist! $$$. That mod_rewrite experiment/tutorial was the culmination of many different advanced mod_rewrite experiments I had done in the past and included most of my very best .htaccess tricks. With the cheatsheet it's no longer Voodoo.. Its just what you do. Now lets dig in!

If you really want to take a look, check out the mod_rewrite.c and mod_rewrite.h files.

Be aware that mod_rewrite (RewriteRule, RewriteBase, and RewriteCond) code is executed for each and every HTTP request that accesses a file in or below the directory where the code resides, so it's always good to limit the code to certain circumstances if readily identifiable.

For example, to limit the next 5 RewriteRules to only be applied to .html and .php files, you can use the following code, which tests if the url does not end in .html or .php and if it doesn't, it will skip the next 5 RewriteRules.

RewriteRule !\.(html|php)$ - [S=5]
RewriteRule ^.*-(vf12|vf13|vf5|vf35|vf1|vf10|vf33|vf8).+$ - [S=1]

.htaccess rewrite examples should begin with:

Options +FollowSymLinks
 
RewriteEngine On
RewriteBase /

Require the www

Options +FollowSymLinks
RewriteEngine On
RewriteBase /
RewriteCond %{HTTP_HOST} !^www\.askapache\.com$ [NC]
RewriteRule ^(.*)$ http://www.askapache.com/$1 [R=301,L]

Loop Stopping Code

Sometimes your rewrites cause infinite loops, stop it with one of these rewrite code snippets.

RewriteCond %{REQUEST_URI} ^/(stats/|missing\.html|failed_auth\.html|error/).* [NC]
RewriteRule .* - [L]
 
RewriteCond %{ENV:REDIRECT_STATUS} 200
RewriteRule .* - [L]

Cache-Friendly File Names

This is probably my favorite, and I use it on every site I work on. It allows me to update my javascript and css files in my visitors cache's simply by naming them differently in the html, on the server they stay the same name. This rewrites all files for /zap/j/anything-anynumber.js to /zap/j/anything.js and /zap/c/anything-anynumber.css to /zap/c/anything.css

RewriteRule ^zap/(j|c)/([a-z]+)-([0-9]+)\.(js|css)$ /zap/$1/$2.$4 [L]

SEO friendly link for non-flash browsers

When you use flash on your site and you properly supply a link to download flash that shows up for non-flash aware browsers, it is nice to use a shortcut to keep your code clean and your external links to a minimum. This code allows me to link to site.com/getflash/ for non-flash aware browsers.

RewriteRule ^getflash/?$ http://www.adobe.com/shockwave/download/download.cgi?P1_Prod_Version=ShockwaveFlash [NC,L,R=307]

Removing the Query_String

On many sites, the page will be displayed for both page.html and page.html?anything=anything, which hurts your SEO with duplicate content. An easy way to fix this issue is to redirect external requests containing a query string to the same uri without the query_string.

RewriteCond %{THE_REQUEST} ^GET\ /.*\;.*\ HTTP/
RewriteCond %{QUERY_STRING} !^$
RewriteRule .* http://www.askapache.com%{REQUEST_URI}? [R=301,L]

Sending requests to a php script

This .htaccess rewrite example invisibly rewrites requests for all Adobe pdf files to be handled by /cgi-bin/pdf-script.php

RewriteRule ^(.+)\.pdf$  /cgi-bin/pdf-script.php?file=$1.pdf [L,NC,QSA]

Setting the language variable based on Client

For sites using multiviews or with multiple language capabilities, it is nice to be able to send the correct language automatically based on the clients preferred language.

RewriteCond %{HTTP:Accept-Language} ^.*(de|es|fr|it|ja|ru|en).*$ [NC]
RewriteRule ^(.*)$ - [env=prefer-language:%1]

Deny Access To Everyone Except PHP fopen

This allows access to all files by php fopen, but denies anyone else.

RewriteEngine On
RewriteBase /
RewriteCond %{THE_REQUEST} ^.+$ [NC]
RewriteRule .* - [F,L]

If you are looking for ways to block or deny specific requests/visitors, then you should definately read Blacklist with mod_rewrite. I give it a 10/10

Deny access to anything in a subfolder except php fopen

This can be very handy if you want to serve media files or special downloads but only through a php proxy script.

RewriteEngine On
RewriteBase /
RewriteCond %{THE_REQUEST} ^[A-Z]{3,9}\ /([^/]+)/.*\ HTTP [NC]
RewriteRule .* - [F,L]

Require no www

Options +FollowSymLinks
RewriteEngine On
RewriteBase /
RewriteCond %{HTTP_HOST} !^askapache\.com$ [NC]
RewriteRule ^(.*)$ http://askapache.com/$1 [R=301,L]

Check for a key in QUERY_STRING

Uses a RewriteCond Directive to check QUERY_STRING for passkey, if it doesn't find it it redirects all requests for anything in the /logged-in/ directory to the /login.php script.

RewriteEngine On
RewriteBase /
RewriteCond %{QUERY_STRING} !passkey
RewriteRule ^/logged-in/(.*)$ /login.php [L]

Removes the QUERY_STRING from the URL

If the QUERY_STRING has any value at all besides blank than the?at the end of /login.php? tells mod_rewrite to remove the QUERY_STRING from login.php and redirect.

RewriteEngine On
RewriteBase /
RewriteCond %{QUERY_STRING} .
RewriteRule ^login.php /login.php? [L]

Fix for infinite loops

An error message related to this isRequest exceeded the limit of 10 internal redirects due to probable configuration error. Use 'LimitInternalRecursion' to increase the limit if necessary. Use 'LogLevel debug' to get a backtrace.or you may seeRequest exceeded the limit,probable configuration error,Use 'LogLevel debug' to get a backtrace, orUse 'LimitInternalRecursion' to increase the limit if necessary

RewriteCond %{ENV:REDIRECT_STATUS} 200
RewriteRule .* - [L]

External Redirect .php files to .html files (SEO friendly)

RewriteRule ^(.*)\.php$ /$1.html [R=301,L]

Internal Redirect .php files to .html files (SEO friendly)

Redirects all files that end in .html to be served from filename.php so it looks like all your pages are .html but really they are .php

RewriteRule ^(.*)\.html$ $1.php [R=301,L]

block access to files during certain hours of the day

Options +FollowSymLinks
RewriteEngine On
RewriteBase /
# If the hour is 16 (4 PM) Then deny all access
RewriteCond %{TIME_HOUR} ^16$
RewriteRule ^.*$ - [F,L]

Rewrite underscores to hyphens for SEO URL

Converts all underscores "_" in urls to hyphens "-" for SEO benefits... See the full article for more info.

Options +FollowSymLinks
RewriteEngine On
RewriteBase /
 
RewriteRule !\.(html|php)$ - [S=4]
RewriteRule ^([^_]*)_([^_]*)_([^_]*)_([^_]*)_(.*)$ $1-$2-$3-$4-$5 [E=uscor:Yes]
RewriteRule ^([^_]*)_([^_]*)_([^_]*)_(.*)$ $1-$2-$3-$4 [E=uscor:Yes]
RewriteRule ^([^_]*)_([^_]*)_(.*)$ $1-$2-$3 [E=uscor:Yes]
RewriteRule ^([^_]*)_(.*)$ $1-$2 [E=uscor:Yes]
 
RewriteCond %{ENV:uscor} ^Yes$
RewriteRule (.*) http://d.com/$1 [R=301,L]

Require the www without hardcoding

Options +FollowSymLinks
RewriteEngine On
RewriteBase /
RewriteCond %{HTTP_HOST} !^www\.[a-z-]+\.[a-z]{2,6} [NC]
RewriteCond %{HTTP_HOST} ([a-z-]+\.[a-z]{2,6})$     [NC]
RewriteRule ^/(.*)$ http://%1/$1 [R=301,L]

Require no subdomain

RewriteEngine On
RewriteBase /
RewriteCond %{HTTP_HOST} \.([a-z-]+\.[a-z]{2,6})$ [NC]
RewriteRule ^/(.*)$ http://%1/$1 [R=301,L]

Require no subdomain

RewriteEngine On
RewriteBase /
RewriteCond %{HTTP_HOST} \.([^\.]+\.[^\.0-9]+)$
RewriteRule ^(.*)$ http://%1/$1 [R=301,L]

Redirecting WordPress Feeds to Feedburner

Full article:Redirecting WordPress Feeds to Feedburner

RewriteEngine On
RewriteBase /
RewriteCond %{REQUEST_URI} ^/feed\.gif$
RewriteRule .* - [L]
 
RewriteCond %{HTTP_USER_AGENT} !^.*(FeedBurner|FeedValidator) [NC]
RewriteRule ^feed/?.*$ http://feeds.feedburner.com/apache/htaccess [L,R=302]
 
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteRule . /index.php [L]

Only allow GET and PUT Request Methods

Article: Request Methods

RewriteEngine On
RewriteBase /
RewriteCond %{REQUEST_METHOD} !^(GET|PUT)
RewriteRule .* - [F]

Prevent Files image/file hotlinking and bandwidth stealing

RewriteEngine On
RewriteBase /
RewriteCond %{HTTP_REFERER} !^$
RewriteCond %{HTTP_REFERER} !^http://(www\.)?askapache.com/.*$ [NC]
RewriteRule \.(gif|jpg|swf|flv|png)$ /feed/ [R=302,L]

Stop browser prefetching

RewriteEngine On
SetEnvIfNoCase X-Forwarded-For .+ proxy=yes
SetEnvIfNoCase X-moz prefetch no_access=yes
 
# block pre-fetch requests with X-moz headers
RewriteCond %{ENV:no_access} yes
RewriteRule .* - [F,L]

This module uses a rule-based rewriting engine (based on a regular-expression parser) to rewrite requested URLs on the fly. It supports an unlimited number of rules and an unlimited number of attached rule conditions for each rule, to provide a really flexible and powerful URL manipulation mechanism. The URL manipulations can depend on various tests, of server variables, environment variables, HTTP headers, or time stamps. Even external database lookups in various formats can be used to achieve highly granular URL matching.

This module operates on the full URLs (including the path-info part) both in per-server context (httpd.conf) and per-directory context (.htaccess) and can generate query-string parts on result. The rewritten result can lead to internal sub-processing, external request redirection or even to an internal proxy throughput.

Further details, discussion, and examples, are provided in the detailed mod_rewrite documentation.

Directives

• RewriteBase
• RewriteCond
• RewriteEngine
• RewriteLock
• RewriteLog
• RewriteLogLevel
• RewriteMap
• RewriteOptions
• RewriteRule

If you aren't already comfortable using mod_rewrite then I recommend this excellent mod_rewrite guide by one of my favorite mod_rewrite gurus that I've met.

htaccess Guide Sections

• htaccess tricks for Webmasters
• HTTP Header control with htaccess
• PHP on Apache tips and tricks
• SEO Redirects without mod_rewrite
• mod_rewrite examples, tips, and tricks
• HTTP Caching and Site Speedups
• Authentication on Apache
• htaccess Security Tricks and Tips
• SSL tips and examples
• Variable Fun (mod_env) Section
• .htaccess Security with MOD_SECURITY
• SetEnvIf and SetEnvIfNoCase Examples

« Search Engine Friendly Redirects | .htaccess Tutorial Index | » Speed up your site with Caching and cache-control

Htaccess Rewrites – Rewrite Tricks and Tips originally appeared on AskApache.com

I was trying to find an official, authoritative list of HTTP Status Codes but I kept finding lists that weren't authoritative or complete. So I searched and found my answer in the Apache HTTP Server source code. Once I had the exact HTTP Status Codes and resulting Error Documents sent by Apache, I researched deeper into HTTP Status Codes by reading as many related RFC's as I could find, and several other software source codes were explored. This is the most authoritative list I know of, if you can do better leave a comment and I'll update it. Another thing to keep in mind, the Status code number itself is what is used by software and hardware to make determinations, the phrase returned by the status code is for the human only and does not have any weight other than informing the user.. So "503 Service Unavailable", "503 Service Temporarily Unavailable", and "503 Get the heck outta here" are all completely valid.

Update March 9, 2009: A lot of sites on the web have updated their HTTP status code lists to include the HTTP Status codes listed on this page, including Wikipedia, IANA, W3C, and others, so rest assured this info is accurate and complete. If you'd like to see how to create custom error pages for all of these errors like mine /show-error-506 , then check out this detailed tutorial I just posted.

Contents

• List of All 57 HTTP Response Status Code
• Quick Start to triggering ErrorDocuments for each Status Code
• Automate the ErrorDocument Triggering
  • The htaccess Code
  • PHP script that gets and outputs the Headers/Content
• Headers and Content Returned
• Apache Source Code
  • httpd.h
  • http_protocol.c

57 APACHE HTTP STATUS RESPONSE CODES

Once I compiled the list of Apache recognized HTTP Status Codes, I was dying to see them all in action (i.e. the corresponding ErrorDocument). At first I thought I would have to create a php or perl script emulating each of the 57 HTTP Status Codes, a tedious undertaking I wasn't about to do. Instead I "asked Apache" by searching the Apache HTTP Documentation for ambiguity sending Status Codes and/or triggering ErrorDocuments with an Apache Directive.
While reading up on mod_alias and the Redirect directive I found:

Apache Docs

Syntax: Redirect [status] URL-path URL The status argument can be used to return other HTTP status codes. Other status codes can be returned by giving the numeric status code as the value of status. If the status is between 300 and 399, the URL argument must be present, otherwise it must be omitted.

100 Continue

ErrorDocument Continue | Sample 100 Continue
This means that the server has received the request headers, and that the client should proceed to send the request body (in case of a request which needs to be sent; for example, a POST request). If the request body is large, sending it to a server when a request has already been rejected based upon inappropriate headers is inefficient. To have a server check if the request could be accepted based on the requests headers alone, a client must send Expect: 100-continue as a header in its initial request (see RFC 2616 14.20 Expect header) and check if a 100 Continue status code is received in response before continuing (or receive 417 Expectation Failed and not continue).

101 Switching Protocols

ErrorDocument Switching Protocols | Sample 101 Switching Protocols
This means the requester has asked the server to switch protocols and the server is acknowledging that it will do so.[3]

102 Processing

ErrorDocument Processing | Sample 102 Processing
(WebDAV) - (RFC 2518 )

200 OK

ErrorDocument OK | Sample 200 OK
Standard response for successful HTTP requests. The actual response will depend on the request method used. In a GET request, the response will contain an entity corresponding to the requested resource. In a POST request the response will contain an entity describing or containing the result of the action.

201 Created

ErrorDocument Created | Sample 201 Created
The request has been fulfilled and resulted in a new resource being created.

202 Accepted

ErrorDocument Accepted | Sample 202 Accepted
The request has been accepted for processing, but the processing has not been completed. The request might or might not eventually be acted upon, as it might be disallowed when processing actually takes place.

203 Non-Authoritative Information

ErrorDocument Non-Authoritative Information | Sample 203 Non-Authoritative Information
The server successfully processed the request, but is returning information that may be from another source.

204 No Content

ErrorDocument No Content | Sample 204 No Content
The server successfully processed the request, but is not returning any content.

205 Reset Content

ErrorDocument Reset Content | Sample 205 Reset Content
The server successfully processed the request, but is not returning any content. Unlike a 204 response, this response requires that the requester reset the document view.

206 Partial Content

ErrorDocument Partial Content | Sample 206 Partial Content
The server is delivering only part of the resource due to a range header sent by the client. This is used by tools like wget to enable resuming of interrupted downloads, or split a download into multiple simultaneous streams.

207 Multi-Status

ErrorDocument Multi-Status | Sample 207 Multi-Status
(WebDAV) - The message body that follows is an XML message and can contain a number of separate response codes, depending on how many sub-requests were made.

226 IM Used

ErrorDocument IM Used | Sample 226 IM Used
The server has fulfilled a GET request for the resource, and the response is a representation of the result of one or more instance-manipulations applied to the current instance. The actual current instance might not be available except by combining this response with other previous or future responses, as appropriate for the specific instance-manipulation(s).

300 Multiple Choices

ErrorDocument Multiple Choices | Sample 300 Multiple Choices
Indicates multiple options for the resource that the client may follow. It, for instance, could be used to present different format options for video, list files with different extensions, or word sense disambiguation.

301 Moved Permanently

ErrorDocument Moved Permanently | Sample 301 Moved Permanently
This and all future requests should be directed to the given URI.

302 Found

ErrorDocument Found | Sample 302 Found
This is the most popular redirect code[citation needed], but also an example of industrial practice contradicting the standard. HTTP/1.0 specification (RFC 1945 ) required the client to perform a temporary redirect (the original describing phrase was "Moved Temporarily"), but popular browsers implemented it as a 303 See Other. Therefore, HTTP/1.1 added status codes 303 and 307 to disambiguate between the two behaviours. However, the majority of Web applications and frameworks still use the 302 status code as if it were the 303.

303 See Other

ErrorDocument See Other | Sample 303 See Other
The response to the request can be found under another URI using a GET method. When received in response to a PUT, it should be assumed that the server has received the data and the redirect should be issued with a separate GET message.

304 Not Modified

ErrorDocument Not Modified | Sample 304 Not Modified
Indicates the resource has not been modified since last requested. Typically, the HTTP client provides a header like the If-Modified-Since header to provide a time against which to compare. Utilizing this saves bandwidth and reprocessing on both the server and client, as only the header data must be sent and received in comparison to the entirety of the page being re-processed by the server, then resent using more bandwidth of the server and client.

305 Use Proxy

ErrorDocument Use Proxy | Sample 305 Use Proxy
Many HTTP clients (such as Mozilla[4] and Internet Explorer) do not correctly handle responses with this status code, primarily for security reasons.

306 Switch Proxy

ErrorDocument Switch Proxy | Sample 306 Switch Proxy
No longer used.

307 Temporary Redirect

ErrorDocument Temporary Redirect | Sample 307 Temporary Redirect
In this occasion, the request should be repeated with another URI, but future requests can still use the original URI. In contrast to 303, the request method should not be changed when reissuing the original request. For instance, a POST request must be repeated using another POST request.

400 Bad Request

ErrorDocument Bad Request | Sample 400 Bad Request
The request contains bad syntax or cannot be fulfilled.

401 Unauthorized

ErrorDocument Unauthorized | Sample 401 Unauthorized
Similar to 403 Forbidden, but specifically for use when authentication is possible but has failed or not yet been provided. The response must include a WWW-Authenticate header field containing a challenge applicable to the requested resource. See Basic access authentication and Digest access authentication.

402 Payment Required

ErrorDocument Payment Required | Sample 402 Payment Required
The original intention was that this code might be used as part of some form of digital cash or micropayment scheme, but that has not happened, and this code has never been used.

403 Forbidden

ErrorDocument Forbidden | Sample 403 Forbidden
The request was a legal request, but the server is refusing to respond to it. Unlike a 401 Unauthorized response, authenticating will make no difference.

404 Not Found

ErrorDocument Not Found | Sample 404 Not Found
The requested resource could not be found but may be available again in the future. Subsequent requests by the client are permissible.

405 Method Not Allowed

ErrorDocument Method Not Allowed | Sample 405 Method Not Allowed
A request was made of a resource using a request method not supported by that resource; for example, using GET on a form which requires data to be presented via POST, or using PUT on a read-only resource.

406 Not Acceptable

ErrorDocument Not Acceptable | Sample 406 Not Acceptable
The requested resource is only capable of generating content not acceptable according to the Accept headers sent in the request.

407 Proxy Authentication Required

ErrorDocument Proxy Authentication Required | Sample 407 Proxy Authentication Required
Required

408 Request Timeout

ErrorDocument Request Timeout | Sample 408 Request Timeout
The server timed out waiting for the request.

409 Conflict

ErrorDocument Conflict | Sample 409 Conflict
Indicates that the request could not be processed because of conflict in the request, such as an edit conflict.

410 Gone

ErrorDocument Gone | Sample 410 Gone
Indicates that the resource requested is no longer available and will not be available again. This should be used when a resource has been intentionally removed; however, it is not necessary to return this code and a 404 Not Found can be issued instead. Upon receiving a 410 status code, the client should not request the resource again in the future. Clients such as search engines should remove the resource from their indexes.

411 Length Required

ErrorDocument Length Required | Sample 411 Length Required
The request did not specify the length of its content, which is required by the requested resource.

412 Precondition Failed

ErrorDocument Precondition Failed | Sample 412 Precondition Failed
The server does not meet one of the preconditions that the requester put on the request.

413 Request Entity Too Large

ErrorDocument Request Entity Too Large | Sample 413 Request Entity Too Large
The request is larger than the server is willing or able to process.

414 Request-URI Too Long

ErrorDocument Request-URI Too Long | Sample 414 Request-URI Too Long
The URI provided was too long for the server to process.

415 Unsupported Media Type

ErrorDocument Unsupported Media Type | Sample 415 Unsupported Media Type
The request did not specify any media types that the server or resource supports. For example the client specified that an image resource should be served as image/svg+xml, but the server cannot find a matching version of the image.

416 Requested Range Not Satisfiable

ErrorDocument Requested Range Not Satisfiable | Sample 416 Requested Range Not Satisfiable
The client has asked for a portion of the file, but the server cannot supply that portion (for example, if the client asked for a part of the file that lies beyond the end of the file).

417 Expectation Failed

ErrorDocument Expectation Failed | Sample 417 Expectation Failed
The server cannot meet the requirements of the Expect request-header field.

418 I'm a teapot

ErrorDocument I'm a teapot | Sample 418 I'm a teapot
The HTCPCP server is a teapot. The responding entity MAY be short and stout. Defined by the April Fools specification RFC 2324. See Hyper Text Coffee Pot Control Protocol for more information.

422 Unprocessable Entity

ErrorDocument Unprocessable Entity | Sample 422 Unprocessable Entity
(WebDAV) (RFC 4918 ) - The request was well-formed but was unable to be followed due to semantic errors.

423 Locked

ErrorDocument Locked | Sample 423 Locked
(WebDAV) (RFC 4918 ) - The resource that is being accessed is locked

424 Failed Dependency

ErrorDocument Failed Dependency | Sample 424 Failed Dependency
(WebDAV) (RFC 4918 ) - The request failed due to failure of a previous request (e.g. a PROPPATCH).

425 Unordered Collection

ErrorDocument Unordered Collection | Sample 425 Unordered Collection
Defined in drafts of WebDav Advanced Collections, but not present in "Web Distributed Authoring and Versioning (WebDAV) Ordered Collections Protocol" (RFC 3648).

426 Upgrade Required

ErrorDocument Upgrade Required | Sample 426 Upgrade Required
(RFC 2817 ) - The client should switch to TLS/1.0.

449 Retry With

ErrorDocument Retry With | Sample 449 Retry With
A Microsoft extension. The request should be retried after doing the appropriate action.

500 Internal Server Error

ErrorDocument Internal Server Error | Sample 500 Internal Server Error
A generic error message, given when no more specific message is suitable.

501 Not Implemented

ErrorDocument Not Implemented | Sample 501 Not Implemented
The server either does not recognise the request method, or it lacks the ability to fulfil the request.

502 Bad Gateway

ErrorDocument Bad Gateway | Sample 502 Bad Gateway
The server was acting as a gateway or proxy and received an invalid response from the upstream server.

503 Service Unavailable

ErrorDocument Service Unavailable | Sample 503 Service Unavailable
The server is currently unavailable (because it is overloaded or down for maintenance). Generally, this is a temporary state.

504 Gateway Timeout

ErrorDocument Gateway Timeout | Sample 504 Gateway Timeout
The server was acting as a gateway or proxy and did not receive a timely request from the upstream server.

505 HTTP Version Not Supported

ErrorDocument HTTP Version Not Supported | Sample 505 HTTP Version Not Supported
The server does not support the HTTP protocol version used in the request.

506 Variant Also Negotiates

ErrorDocument Variant Also Negotiates | Sample 506 Variant Also Negotiates
(RFC 2295 ) - Transparent content negotiation for the request, results in a circular reference.

507 Insufficient Storage

ErrorDocument Insufficient Storage | Sample 507 Insufficient Storage
(WebDAV) (RFC 4918 )

509 Bandwidth Limit Exceeded

ErrorDocument Bandwidth Limit Exceeded | Sample 509 Bandwidth Limit Exceeded
(Apache bw/limited extension) - This status code, while used by many servers, is not specified in any RFCs.

510 Not Extended

ErrorDocument Not Extended | Sample 510 Not Extended
(RFC 2774 ) - Further extensions to the request are required for the server to fulfil it.

1xx Info / Informational

HTTP_INFO - Request received, continuing process. Indicates a provisional response, consisting only of the Status-Line and optional headers, and is terminated by an empty line.

• 100 Continue - HTTP_CONTINUE
• 101 Switching Protocols - HTTP_SWITCHING_PROTOCOLS
• 102 Processing - HTTP_PROCESSING

2xx Success / OK

HTTP_SUCCESS - The action was successfully received, understood, and accepted. Indicates that the client's request was successfully received, understood, and accepted.

• 200 OK - HTTP_OK
• 201 Created - HTTP_CREATED
• 202 Accepted - HTTP_ACCEPTED
• 203 Non-Authoritative Information - HTTP_NON_AUTHORITATIVE
• 204 No Content - HTTP_NO_CONTENT
• 205 Reset Content - HTTP_RESET_CONTENT
• 206 Partial Content - HTTP_PARTIAL_CONTENT
• 207 Multi-Status - HTTP_MULTI_STATUS

3xx Redirect

HTTP_REDIRECT - The client must take additional action to complete the request. Indicates that further action needs to be taken by the user-agent in order to fulfill the request. The action required may be carried out by the user agent without interaction with the user if and only if the method used in the second request is GET or HEAD. A user agent should not automatically redirect a request more than 5 times, since such redirections usually indicate an infinite loop.

• 300 Multiple Choices - HTTP_MULTIPLE_CHOICES
• 301 Moved Permanently - HTTP_MOVED_PERMANENTLY
• 302 Found - HTTP_MOVED_TEMPORARILY
• 303 See Other - HTTP_SEE_OTHER
• 304 Not Modified - HTTP_NOT_MODIFIED
• 305 Use Proxy - HTTP_USE_PROXY
• 306 unused - UNUSED
• 307 Temporary Redirect - HTTP_TEMPORARY_REDIRECT

4xx Client Error

HTTP_CLIENT_ERROR - The request contains bad syntax or cannot be fulfilled. Indicates case where client seems to have erred. Except when responding to a HEAD request, the server should include an entity containing an explanation of the error situation, and whether it is a temporary or permanent condition.

• 400 Bad Request - HTTP_BAD_REQUEST
• 401 Authorization Required - HTTP_UNAUTHORIZED
• 402 Payment Required - HTTP_PAYMENT_REQUIRED
• 403 Forbidden - HTTP_FORBIDDEN
• 404 Not Found - HTTP_NOT_FOUND
• 405 Method Not Allowed - HTTP_METHOD_NOT_ALLOWED
• 406 Not Acceptable - HTTP_NOT_ACCEPTABLE
• 407 Proxy Authentication Required - HTTP_PROXY_AUTHENTICATION_REQUIRED
• 408 Request Time-out - HTTP_REQUEST_TIME_OUT
• 409 Conflict - HTTP_CONFLICT
• 410 Gone - HTTP_GONE
• 411 Length Required - HTTP_LENGTH_REQUIRED
• 412 Precondition Failed - HTTP_PRECONDITION_FAILED
• 413 Request Entity Too Large - HTTP_REQUEST_ENTITY_TOO_LARGE
• 414 Request-URI Too Large - HTTP_REQUEST_URI_TOO_LARGE
• 415 Unsupported Media Type - HTTP_UNSUPPORTED_MEDIA_TYPE
• 416 Requested Range Not Satisfiable - HTTP_RANGE_NOT_SATISFIABLE
• 417 Expectation Failed - HTTP_EXPECTATION_FAILED
• 418 I'm a teapot - UNUSED
• 419 unused - UNUSED
• 420 unused - UNUSED
• 421 unused - UNUSED
• 422 Unprocessable Entity - HTTP_UNPROCESSABLE_ENTITY
• 423 Locked - HTTP_LOCKED
• 424 Failed Dependency - HTTP_FAILED_DEPENDENCY
• 425 No code - HTTP_NO_CODE
• 426 Upgrade Required - HTTP_UPGRADE_REQUIRED

5xx Server Error

HTTP_SERVER_ERROR - The server failed to fulfill an apparently valid request. Indicate cases in which the server is aware that it has erred or is incapable of performing the request. Except when responding to a HEAD request, the server should include an entity containing an explanation of the error situation, and whether it is a temporary or permanent condition. User agents should display any included entity to the user. These response codes are applicable to any request method.

• 500 Internal Server Error - HTTP_INTERNAL_SERVER_ERROR
• 501 Method Not Implemented - HTTP_NOT_IMPLEMENTED
• 502 Bad Gateway - HTTP_BAD_GATEWAY
• 503 Service Temporarily Unavailable - HTTP_SERVICE_UNAVAILABLE
• 504 Gateway Time-out - HTTP_GATEWAY_TIME_OUT
• 505 HTTP Version Not Supported - HTTP_VERSION_NOT_SUPPORTED
• 506 Variant Also Negotiates - HTTP_VARIANT_ALSO_VARIES
• 507 Insufficient Storage - HTTP_INSUFFICIENT_STORAGE
• 508 unused - UNUSED
• 509 unused - UNUSED
• 510 Not Extended - HTTP_NOT_EXTENDED

Quick Start to triggering ErrorDocuments for each Status Code

Let start with a quick and easy example. Add the following Redirect rules to your htaccess file, then open your browser and goto each url like yoursite.com/e/400. Don't create an /e/ directory or any files.

Redirect 400 /e/400
Redirect 503 /e/503
Redirect 405 /e/405

Automate the ErrorDocument Triggering

The htaccess Redirects

When a Status code is encountered, Apache outputs the Header and the ErrorDocument for that error code. So you can view any Header and the default ErrorDocument, by causing that numerical error code, which is caused by the Status Code.

For instance, if you request a file that doesn't exist, a 404 Not Found Header is issued and the corresponding ErrorDocument is served with the 404 Not Found Header.

Redirect 100 /e/100
Redirect 101 /e/101
Redirect 102 /e/102
Redirect 200 /e/200
Redirect 201 /e/201
Redirect 202 /e/202
Redirect 203 /e/203
Redirect 204 /e/204
Redirect 205 /e/205
Redirect 206 /e/206
Redirect 207 /e/207
Redirect 300 /e/300 http://www.askapache.com/?s=300
Redirect 301 /e/301 http://www.askapache.com/?s=301
Redirect 302 /e/302 http://www.askapache.com/?s=302
Redirect 303 /e/303 http://www.askapache.com/?s=303
Redirect 304 /e/304 http://www.askapache.com/?s=304
Redirect 305 /e/305 http://www.askapache.com/?s=305
Redirect 306 /e/306 http://www.askapache.com/?s=306
Redirect 307 /e/307 http://www.askapache.com/?s=307
Redirect 400 /e/400
Redirect 401 /e/401
Redirect 402 /e/402
Redirect 403 /e/403
Redirect 404 /e/404
Redirect 405 /e/405
Redirect 406 /e/406
Redirect 407 /e/407
Redirect 408 /e/408
Redirect 409 /e/409
Redirect 410 /e/410
Redirect 411 /e/411
Redirect 412 /e/412
Redirect 413 /e/413
Redirect 414 /e/414
Redirect 415 /e/415
Redirect 416 /e/416
Redirect 417 /e/417
Redirect 418 /e/418
Redirect 419 /e/419
Redirect 420 /e/420
Redirect 421 /e/421
Redirect 422 /e/422
Redirect 423 /e/423
Redirect 424 /e/424
Redirect 425 /e/425
Redirect 426 /e/426
Redirect 500 /e/500
Redirect 501 /e/501
Redirect 502 /e/502
Redirect 503 /e/503
Redirect 504 /e/504
Redirect 505 /e/505
Redirect 506 /e/506
Redirect 507 /e/507
Redirect 508 /e/508
Redirect 509 /e/509
Redirect 510 /e/510

PHP script that gets and outputs the Headers/Content

Now all I have to do is add 57 Redirect Directives to my htaccess, and then request each of them 1 at a time from my browser to see the result, and use a packet sniffing program like WireShark to see the Headers. Uh, scratch that, that would take way too long!

Instead I hacked up a simple php script using cURL to automate sending GET Requests to each of the 57 Redirect URL-paths. A side benefit of using the php script is that it performs all 57 Requests concurrently and saves each Requests returned headers and content to an output buffer. After all 57 have been queried, the output buffer is flushed to the browser.

<?php
$SITENAME='http://www.askapache.com';
 
$CODES = array(array('100','101','102'),
array('200','201','202','203','204','205','206','207'),
array('300','301','302','303','304','305','306','307'),
array('400','401','402','403','404','405','406','407','408','409','410','411','412','413',
'414','415','416','417','418','419','420','421','422','423','424','425','426'),
array('500','501','502','503','504','505','506','507','508','509','510'));
 
$TMPSAVETO='/tmp/'.time().'.txt';
 
# if file exists then delete it
if(is_file($TMPSAVETO))unlink($TMPSAVETO);
 
foreach($CODES as $keyd => $res)
{
foreach($res as $key)
{
$ch = curl_init("$SITENAME/e/$key");
$fp = fopen ($TMPSAVETO, "a");
curl_setopt ($ch, CURLOPT_FILE, $fp);
curl_setopt ($ch, CURLOPT_FOLLOWLOCATION ,1);
curl_setopt ($ch, CURLOPT_HEADER ,1);
curl_exec ($ch);
curl_close ($ch);
fclose ($fp);
}
}
$OUT='';
ob_start();
header ("Content-Type: text/plain;");
readfile($TMPSAVETO);
$OUT=ob_get_clean();
echo $OUT;
unlink($TMPSAVETO);
exit;
?>

Headers and Content Returned

100 Continue

HTTP/1.1 100 Continue
<html>
<head>
<title>100 Continue</title>
</head>
<body>
<h1>Continue</h1>
<p>The server encountered an internal error or misconfigurationand was unable to complete your request.</p>
<p>Please contact the server administrator, a@s.com and inform them of the time the error occurred, and anything you might have done that may have caused the error.</p>
<p>More information about this error may be available in the server error log.</p>
</body>
</html>

101 Switching Protocols

HTTP/1.1 101 Switching Protocols<html>
<head>
<title>101 Switching Protocols</title>
</head>
<body>
<h1>Switching Protocols</h1>
<p>The server encountered an internal error or misconfigurationand was unable to complete your request.</p>
<p>Please contact the server administrator, a@s.com and inform them of the time the error occurred, and anything you might have done that may have caused the error.</p>
<p>More information about this error may be available in the server error log.</p>
</body>
</html>

102 Processing

HTTP/1.1 102 Processing
X-Pad: avoid browser bug<html>
<head>
<title>102 Processing</title>
</head>
<body>
<h1>Processing</h1>
<p>The server encountered an internal error or misconfigurationand was unable to complete your request.</p>
<p>Please contact the server administrator, a@s.com and inform them of the time the error occurred, and anything you might have done that may have caused the error.</p>
<p>More information about this error may be available in the server error log.</p>
</body>
</html>

200 OK

HTTP/1.1 200 OK
<html>
<head>
<title>200 OK</title>
</head>
<body>
<h1>OK</h1>
<p>The server encountered an internal error or misconfigurationand was unable to complete your request.</p>
<p>Please contact the server administrator, a@s.com and inform them of the time the error occurred, and anything you might have done that may have caused the error.</p>
<p>More information about this error may be available in the server error log.</p>
</body>
</html>

201 Created

HTTP/1.1 201 Created
<html>
<head>
<title>201 Created</title>
</head>
<body>
<h1>Created</h1>
<p>The server encountered an internal error or misconfigurationand was unable to complete your request.</p>
<p>Please contact the server administrator, a@s.com and inform them of the time the error occurred, and anything you might have done that may have caused the error.</p>
<p>More information about this error may be available in the server error log.</p>
</body>
</html>

202 Accepted

HTTP/1.1 202 Accepted
<html>
<head>
<title>202 Accepted</title>
</head>
<body>
<h1>Accepted</h1>
<p>The server encountered an internal error or misconfigurationand was unable to complete your request.</p>
<p>Please contact the server administrator, a@s.com and inform them of the time the error occurred, and anything you might have done that may have caused the error.</p>
<p>More information about this error may be available in the server error log.</p>
</body>
</html>

203 Non-Authoritative Information

HTTP/1.1 203 Non-Authoritative Information
<html>
<head>
<title>203 Non-Authoritative Information</title>
</head>
<body>
<h1>Non-Authoritative Information</h1>
<p>The server encountered an internal error or misconfigurationand was unable to complete your request.</p>
<p>Please contact the server administrator, a@s.com and inform them of the time the error occurred, and anything you might have done that may have caused the error.</p>
<p>More information about this error may be available in the server error log.</p>
</body>
</html>

204 No Content

HTTP/1.1 204 No Content
Content-Type: text/plain; charset=UTF-8

205 Reset Content

HTTP/1.1 205 Reset Content<html>
<head>
<title>205 Reset Content</title>
</head>
<body>
<h1>Reset Content</h1>
<p>The server encountered an internal error or misconfigurationand was unable to complete your request.</p>
<p>Please contact the server administrator, a@s.com and inform them of the time the error occurred, and anything you might have done that may have caused the error.</p>
<p>More information about this error may be available in the server error log.</p>
</body>
</html>

206 Partial Content

HTTP/1.1 206 Partial Content<html>
<head>
<title>206 Partial Content</title>
</head>
<body>
<h1>Partial Content</h1>
<p>The server encountered an internal error or misconfigurationand was unable to complete your request.</p>
<p>Please contact the server administrator, a@s.com and inform them of the time the error occurred, and anything you might have done that may have caused the error.</p>
<p>More information about this error may be available in the server error log.</p>
</body>
</html>

207 Multi-Status

HTTP/1.1 207 Multi-Status
X-Pad: avoid browser bug<html>
<head>
<title>207 Multi-Status</title>
</head>
<body>
<h1>Multi-Status</h1>
<p>The server encountered an internal error or misconfigurationand was unable to complete your request.</p>
<p>Please contact the server administrator, a@s.com and inform them of the time the error occurred, and anything you might have done that may have caused the error.</p>
<p>More information about this error may be available in the server error log.</p>
</body>
</html>

300 Multiple Choices

HTTP/1.1 300 Multiple Choices
Location: http://www.askapache.com/?s=300<html>
<head>
<title>300 Multiple Choices</title>
</head>
<body>
<h1>Multiple Choices</h1>
</body>
</html>

301 Moved Permanently

HTTP/1.1 301 Moved Permanently
Location: http://www.askapache.com/?s=301<html>
<head>
<title>301 Moved Permanently</title>
</head>
<body>
<h1>Moved Permanently</h1>
<p>The document has moved  <a href="http://www.askapache.com/?s=301">here</a> .</p>
</body>
</html>

302 Found

HTTP/1.1 302 Found
Location: http://www.askapache.com/?s=302<html>
<head>
<title>302 Found</title>
</head>
<body>
<h1>Found</h1>
<p>The document has moved  <a href="http://www.askapache.com/?s=302">here</a> .</p>
</body>
</html>

303 See Other

HTTP/1.1 303 See Other
Location: http://www.askapache.com/?s=303<html>
<head>
<title>303 See Other</title>
</head>
<body>
<h1>See Other</h1>
<p>The answer to your request is located  <a href="http://www.askapache.com/?s=303">here</a> .</p>
</body>
</html>

304 Not Modified

HTTP/1.1 304 Not Modified

305 Use Proxy

HTTP/1.1 305 Use Proxy
Location: http://www.askapache.com/?s=305<html>
<head>
<title>305 Use Proxy</title>
</head>
<body>
<h1>Use Proxy</h1>
<p>This resource is only accessible through the proxy
    http://www.askapache.com/?s=305<br />You will need to configure your client to use that proxy.</p>
</body>
</html>

306 unused

HTTP/1.1 306 unused
Location: http://www.askapache.com/?s=306<html>
<head>
<title>306 unused</title>
</head>
<body>
<h1>unused</h1>
<p>The server encountered an internal error or misconfigurationand was unable to complete your request.</p>
<p>Please contact the server administrator, a@s.com and inform them of the time the error occurred, and anything you might have done that may have caused the error.</p>
<p>More information about this error may be available in the server error log.</p>
</body>
</html>

307 Temporary Redirect

HTTP/1.1 307 Temporary Redirect
Location: http://www.askapache.com/?s=307<html>
<head>
<title>307 Temporary Redirect</title>
</head>
<body>
<h1>Temporary Redirect</h1>
<p>The document has moved  <a href="http://www.askapache.com/?s=307">here</a> .</p>
</body>
</html>

400 Bad Request

HTTP/1.1 400 Bad Request
Connection: close<html>
<head>
<title>400 Bad Request</title>
</head>
<body>
<h1>Bad Request</h1>
<p>Your browser sent a request that this server could not understand.</p>
</body>
</html>

401 Authorization Required

HTTP/1.1 401 Authorization Required<html>
<head>
<title>401 Authorization Required</title>
</head>
<body>
<h1>Authorization Required</h1>
<p>This server could not verify that you
    are authorized to access the document
    requested.  Either you supplied the wrong
    credentials (e.g., bad password), or your
    browser doesn't understand how to supply
    the credentials required.</p>
<p>Additionally, a 404 Not Found error was encountered while trying to use an ErrorDocument to handle the request.</p>
</body>
</html>

402 Payment Required

HTTP/1.1 402 Payment Required<html>
<head>
<title>402 Payment Required</title>
</head>
<body>
<h1>Payment Required</h1>
<p>The server encountered an internal error or misconfigurationand was unable to complete your request.</p>
<p>Please contact the server administrator, a@s.com and inform them of the time the error occurred, and anything you might have done that may have caused the error.</p>
<p>More information about this error may be available in the server error log.</p>
</body>
</html>

403 Forbidden

HTTP/1.1 403 Forbidden<html>
<head>
<title>403 Forbidden</title>
</head>
<body>
<h1>Forbidden</h1>
<p>You don't have permission to access /e/403
    on this server.</p>
<p>Additionally, a 404 Not Found error was encountered while trying to use an ErrorDocument to handle the request.</p>
</body>
</html>

404 Not Found

HTTP/1.1 404 Not Found<html>
<head>
<title>404 Not Found</title>
</head>
<body>
<h1>Not Found</h1>
<p>The requested URL /e/404 was not found on this server.</p>
</body>
</html>

NOTE:
You will most definately want to check out and use the Google 404 Error Page if you run WordPress.

405 Method Not Allowed

HTTP/1.1 405 Method Not Allowed
Allow: TRACE
<html>
<head>
<title>405 Method Not Allowed</title>
</head>
<body>
<h1>Method Not Allowed</h1>
<p>The requested method GET is not allowed for the URL /e/405.</p>
</body>
</html>

406 Not Acceptable

HTTP/1.1 406 Not Acceptable
<html>
<head>
<title>406 Not Acceptable</title>
</head>
<body>
<h1>Not Acceptable</h1>
<p>An appropriate representation of the requested resource /e/406 could not be found on this server.</p>
</body>
</html>

407 Proxy Authentication Required

HTTP/1.1 407 Proxy Authentication Required<html>
<head>
<title>407 Proxy Authentication Required</title>
</head>
<body>
<h1>Proxy Authentication Required</h1>
<p>This server could not verify that you
    are authorized to access the document
    requested.  Either you supplied the wrong
    credentials (e.g., bad password), or your
    browser doesn't understand how to supply
    the credentials required.</p>
</body>
</html>

408 Request Time-out

HTTP/1.1 408 Request Time-out
Connection: close
<html>
<head>
<title>408 Request Time-out</title>
</head>
<body>
<h1>Request Time-out</h1>
<p>Server timeout waiting for the HTTP request from the client.</p>
</body>
</html>

409 Conflict

HTTP/1.1 409 Conflict
<html>
<head>
<title>409 Conflict</title>
</head>
<body>
<h1>Conflict</h1>
<p>The server encountered an internal error or misconfigurationand was unable to complete your request.</p>
<p>Please contact the server administrator, a@s.com and inform them of the time the error occurred, and anything you might have done that may have caused the error.</p>
<p>More information about this error may be available in the server error log.</p>
</body>
</html>

410 Gone

HTTP/1.1 410 Gone
<html>
<head>
<title>410 Gone</title>
</head>
<body>
<h1>Gone</h1>
<p>The requested resource<br />/e/410<br />is no longer available on this server and there is no forwarding address.
    Please remove all references to this resource.</p>
</body>
</html>

411 Length Required

HTTP/1.1 411 Length Required
Connection: close
<html>
<head>
<title>411 Length Required</title>
</head>
<body>
<h1>Length Required</h1>
<p>A request of the requested method GET requires a valid Content-length.</p>
</body>
</html>

412 Precondition Failed

HTTP/1.1 412 Precondition Failed
<html>
<head>
<title>412 Precondition Failed</title>
</head>
<body>
<h1>Precondition Failed</h1>
<p>The precondition on the request for the URL /e/412 evaluated to false.</p>
</body>
</html>

413 Request Entity Too Large

HTTP/1.1 413 Request Entity Too Large
Connection: close<html>
<head>
<title>413 Request Entity Too Large</title>
</head>
<body>
<h1>Request Entity Too Large</h1>
The requested resource<br />/e/413<br />does not allow request data with GET requests, or the amount of data provided in
the request exceeds the capacity limit.
</body>
</html>

414 Request-URI Too Large

HTTP/1.1 414 Request-URI Too Large
Connection: close<html>
<head>
<title>414 Request-URI Too Large</title>
</head>
<body>
<h1>Request-URI Too Large</h1>
<p>The requested URL's length exceeds the capacity
    limit for this server.</p>
</body>
</html>

415 Unsupported Media Type

HTTP/1.1 415 Unsupported Media Type<html>
<head>
<title>415 Unsupported Media Type</title>
</head>
<body>
<h1>Unsupported Media Type</h1>
<p>The supplied request data is not in a format
    acceptable for processing by this resource.</p>
</body>
</html>

416 Requested Range Not Satisfiable

HTTP/1.1 416 Requested Range Not Satisfiable

417 Expectation Failed

HTTP/1.1 417 Expectation Failed<html>
<head>
<title>417 Expectation Failed</title>
</head>
<body>
<h1>Expectation Failed</h1>
<p>The expectation given in the Expect request-header
    field could not be met by this server.</p>
<p>The client sent<pre>
    Expect: </p>
</body>
</html>

418 I'm a teapot

HTTP/1.1 418 I'm a teapot<html>
<head>
<title>418 I'm a teapot</title>
</head>
<body>
<h1>I'm a teapot</h1>
<p>Unfortunately this coffee machine is out of coffee.</p>
</body>
</html>

419 unused

HTTP/1.1 419 unused<html>
<head>
<title>419 unused</title>
</head>
<body>
<h1>unused</h1>
<p>The server encountered an internal error or misconfigurationand was unable to complete your request.</p>
<p>Please contact the server administrator, a@s.com and inform them of the time the error occurred, and anything you might have done that may have caused the error.</p>
<p>More information about this error may be available in the server error log.</p>
</body>
</html>

420 unused

HTTP/1.1 420 unused<html>
<head>
<title>420 unused</title>
</head>
<body>
<h1>unused</h1>
<p>The server encountered an internal error or misconfigurationand was unable to complete your request.</p>
<p>Please contact the server administrator, a@s.com and inform them of the time the error occurred, and anything you might have done that may have caused the error.</p>
<p>More information about this error may be available in the server error log.</p>
</body>
</html>

421 unused

HTTP/1.1 421 unused<html>
<head>
<title>421 unused</title>
</head>
<body>
<h1>unused</h1>
<p>The server encountered an internal error or misconfigurationand was unable to complete your request.</p>
<p>Please contact the server administrator, a@s.com and inform them of the time the error occurred, and anything you might have done that may have caused the error.</p>
<p>More information about this error may be available in the server error log.</p>
</body>
</html>

422 Unprocessable Entity

HTTP/1.1 422 Unprocessable Entity<html>
<head>
<title>422 Unprocessable Entity</title>
</head>
<body>
<h1>Unprocessable Entity</h1>
<p>The server understands the media type of the
    request entity, but was unable to process the
    contained instructions.</p>
</body>
</html>

423 Locked

HTTP/1.1 423 Locked<html>
<head>
<title>423 Locked</title>
</head>
<body>
<h1>Locked</h1>
<p>The requested resource is currently locked.
    The lock must be released or proper identification
    given before the method can be applied.</p>
</body>
</html>

424 Failed Dependency

HTTP/1.1 424 Failed Dependency<html>
<head>
<title>424 Failed Dependency</title>
</head>
<body>
<h1>Failed Dependency</h1>
<p>The method could not be performed on the resource
    because the requested action depended on another
    action and that other action failed.</p>
</body>
</html>

425 No code

HTTP/1.1 425 No code<html>
<head>
<title>425 No code</title>
</head>
<body>
<h1>No code</h1>
<p>The server encountered an internal error or misconfigurationand was unable to complete your request.</p>
<p>Please contact the server administrator, a@s.com and inform them of the time the error occurred, and anything you might have done that may have caused the error.</p>
<p>More information about this error may be available in the server error log.</p>
</body>
</html>

426 Upgrade Required

HTTP/1.1 426 Upgrade Required<html>
<head>
<title>426 Upgrade Required</title>
</head>
<body>
<h1>Upgrade Required</h1>
<p>The requested resource can only be retrieved
    using SSL.  The server is willing to upgrade the current
    connection to SSL, but your client doesn't support it.
    Either upgrade your client, or try requesting the page
    using https:// </p>
</body>
</html>

500 Internal Server Error

HTTP/1.1 500 Internal Server Error
Connection: close<html>
<head>
<title>500 Internal Server Error</title>
</head>
<body>
<h1>Internal Server Error</h1>
<p>The server encountered an internal error or misconfigurationand was unable to complete your request.</p>
<p>Please contact the server administrator, a@s.com and inform them of the time the error occurred, and anything you might have done that may have caused the error.</p>
<p>More information about this error may be available in the server error log.</p>
<p>Additionally, a 404 Not Found error was encountered while trying to use an ErrorDocument to handle the request.</p>
</body>
</html>

501 Method Not Implemented

HTTP/1.1 501 Method Not Implemented
Allow: TRACE
Connection: close<html>
<head>
<title>501 Method Not Implemented</title>
</head>
<body>
<h1>Method Not Implemented</h1>
<p>GET to /e/501 not supported.</p>
</body>
</html>

502 Bad Gateway

HTTP/1.1 502 Bad Gateway
X-Pad: avoid browser bug<html>
<head>
<title>502 Bad Gateway</title>
</head>
<body>
<h1>Bad Gateway</h1>
<p>The proxy server received an invalid
    response from an upstream server.</p>
</body>
</html>

503 Service Temporarily Unavailable

HTTP/1.1 503 Service Temporarily Unavailable
Connection: close<html>
<head>
<title>503 Service Temporarily Unavailable</title>
</head>
<body>
<h1>Service Temporarily Unavailable</h1>
<p>The server is temporarily unable to service your
    request due to maintenance downtime or capacity
    problems. Please try again later.</p>
</body>
</html>

504 Gateway Time-out

HTTP/1.1 504 Gateway Time-out<html>
<head>
<title>504 Gateway Time-out</title>
</head>
<body>
<h1>Gateway Time-out</h1>
<p>The proxy server did not receive a timely response
    from the upstream server.</p>
</body>
</html>

505 HTTP Version Not Supported

HTTP/1.1 505 HTTP Version Not Supported<html>
<head>
<title>505 HTTP Version Not Supported</title>
</head>
<body>
<h1>HTTP Version Not Supported</h1>
<p>The server encountered an internal error or misconfigurationand was unable to complete your request.</p>
<p>Please contact the server administrator, a@s.com and inform them of the time the error occurred, and anything you might have done that may have caused the error.</p>
<p>More information about this error may be available in the server error log.</p>
</body>
</html>

506 Variant Also Negotiates

HTTP/1.1 506 Variant Also Negotiates<html>
<head>
<title>506 Variant Also Negotiates</title>
</head>
<body>
<h1>Variant Also Negotiates</h1>
<p>A variant for the requested resource
    <pre>
    /e/506
    </pre>
    is itself a negotiable resource. This indicates a configuration error.</p>
</body>
</html>

507 Insufficient Storage

HTTP/1.1 507 Insufficient Storage<html>
<head>
<title>507 Insufficient Storage</title>
</head>
<body>
<h1>Insufficient Storage</h1>
<p>The method could not be performed on the resource
    because the server is unable to store the
    representation needed to successfully complete the
    request.  There is insufficient free space left in
    your storage allocation.</p>
</body>
</html>

508 unused

HTTP/1.1 508 unused<html>
<head>
<title>508 unused</title>
</head>
<body>
<h1>unused</h1>
<p>The server encountered an internal error or misconfigurationand was unable to complete your request.</p>
<p>Please contact the server administrator, a@s.com and inform them of the time the error occurred, and anything you might have done that may have caused the error.</p>
<p>More information about this error may be available in the server error log.</p>
</body>
</html>

509 unused

HTTP/1.1 509 unused
<html>
<head>
<title>509 unused</title>
</head>
<body>
<h1>unused</h1>
<p>The server encountered an internal error or misconfigurationand was unable to complete your request.</p>
<p>Please contact the server administrator, a@s.com and inform them of the time the error occurred, and anything you might have done that may have caused the error.</p>
<p>More information about this error may be available in the server error log.</p>
</body>
</html>

510 Not Extended

HTTP/1.1 510 Not Extended
X-Pad: avoid browser bug
<html>
<head>
<title>510 Not Extended</title>
</head>
<body>
<h1>Not Extended</h1>
<p>A mandatory extension policy in the request is not
    accepted by the server for this resource.</p>
</body>
</html>

Apache Source Code

httpd.h

From httpd.h

/**
* The size of the static array in http_protocol.c for storing
* all of the potential response status-lines (a sparse table).
* A future version should dynamically generate the apr_table_t at startup.
*/
#define RESPONSE_CODES 57
#define HTTP_CONTINUE            100
#define HTTP_SWITCHING_PROTOCOLS       101
#define HTTP_PROCESSING          102
#define HTTP_OK              200
#define HTTP_CREATED             201
#define HTTP_ACCEPTED            202
#define HTTP_NON_AUTHORITATIVE       203
#define HTTP_NO_CONTENT          204
#define HTTP_RESET_CONTENT         205
#define HTTP_PARTIAL_CONTENT         206
#define HTTP_MULTI_STATUS          207
#define HTTP_MULTIPLE_CHOICES        300
#define HTTP_MOVED_PERMANENTLY       301
 
#define HTTP_MOVED_TEMPORARILY       302
#define HTTP_SEE_OTHER           303
#define HTTP_NOT_MODIFIED          304
#define HTTP_USE_PROXY           305
#define HTTP_TEMPORARY_REDIRECT      307
#define HTTP_BAD_REQUEST           400
#define HTTP_UNAUTHORIZED          401
#define HTTP_PAYMENT_REQUIRED        402
#define HTTP_FORBIDDEN           403
#define HTTP_NOT_FOUND           404
#define HTTP_METHOD_NOT_ALLOWED      405
#define HTTP_NOT_ACCEPTABLE        406
#define HTTP_PROXY_AUTHENTICATION_REQUIRED 407
#define HTTP_REQUEST_TIME_OUT        408
#define HTTP_CONFLICT            409
#define HTTP_GONE              410
#define HTTP_LENGTH_REQUIRED         411
#define HTTP_PRECONDITION_FAILED       412
#define HTTP_REQUEST_ENTITY_TOO_LARGE    413
#define HTTP_REQUEST_URI_TOO_LARGE     414
#define HTTP_UNSUPPORTED_MEDIA_TYPE    415
#define HTTP_RANGE_NOT_SATISFIABLE     416
#define HTTP_EXPECTATION_FAILED      417
#define HTTP_UNPROCESSABLE_ENTITY      422
#define HTTP_LOCKED            423
#define HTTP_FAILED_DEPENDENCY       424
#define HTTP_UPGRADE_REQUIRED        426
#define HTTP_INTERNAL_SERVER_ERROR     500
#define HTTP_NOT_IMPLEMENTED         501
#define HTTP_BAD_GATEWAY           502
#define HTTP_SERVICE_UNAVAILABLE       503
#define HTTP_GATEWAY_TIME_OUT        504
#define HTTP_VERSION_NOT_SUPPORTED     505
#define HTTP_VARIANT_ALSO_VARIES       506
#define HTTP_INSUFFICIENT_STORAGE      507
#define HTTP_NOT_EXTENDED          510
 
/** is the status code informational */
#define ap_is_HTTP_INFO(x)     (((x) >= 100)&&((x) < 200))
/** is the status code OK ?*/
#define ap_is_HTTP_SUCCESS(x)    (((x) >= 200)&&((x) < 300))
/** is the status code a redirect */
#define ap_is_HTTP_REDIRECT(x)   (((x) >= 300)&&((x) < 400))
/** is the status code a error (client or server) */
#define ap_is_HTTP_ERROR(x)    (((x) >= 400)&&((x) < 600))
/** is the status code a client error  */
#define ap_is_HTTP_CLIENT_ERROR(x) (((x) >= 400)&&((x) < 500))
/** is the status code a server error  */
#define ap_is_HTTP_SERVER_ERROR(x) (((x) >= 500)&&((x) < 600))
/** is the status code a (potentially) valid response code?  */
#define ap_is_HTTP_VALID_RESPONSE(x) (((x) >= 100)&&((x) < 600))
 
/** should the status code drop the connection */
#define ap_status_drops_connection(x) \
(((x) == HTTP_BAD_REQUEST)       || \
((x) == HTTP_REQUEST_TIME_OUT)    || \
((x) == HTTP_LENGTH_REQUIRED)     || \
((x) == HTTP_REQUEST_ENTITY_TOO_LARGE) || \
((x) == HTTP_REQUEST_URI_TOO_LARGE) || \
((x) == HTTP_INTERNAL_SERVER_ERROR) || \
((x) == HTTP_SERVICE_UNAVAILABLE) || \
((x) == HTTP_NOT_IMPLEMENTED))

HTTP_INFO

Is the status code (x) informational?

x >= 100 && x < 200

HTTP_SUCCESS

Is the status code (x) OK?

x >= 200 && x < 300

HTTP_REDIRECT

Is the status code (x) a redirect?

x >= 300 && x < 400

HTTP_ERROR

Is the status code (x) a error (client or server)?

x >= 400 && x < 600

HTTP_CLIENT_ERROR

Is the status code (x) a client error?

x >= 400 && x < 500

HTTP_SERVER_ERROR

Is the status code (x) a server error?

x >= 500 && x < 600

HTTP_VALID_RESPONSE

Is the status code (x) a (potentially) valid response code?

x >= 100 && x < 600

http_protocol.c

From http_protocol.c

static const char * status_lines[RESPONSE_CODES] =
static const char * const status_lines[RESPONSE_CODES] =
"100 Continue",
"101 Switching Protocols",
"102 Processing",
"200 OK",
"201 Created",
"202 Accepted",
"203 Non-Authoritative Information",
"204 No Content",
"205 Reset Content",
"206 Partial Content",
"207 Multi-Status",
"300 Multiple Choices",
"301 Moved Permanently",
"302 Found",
"303 See Other",
"304 Not Modified",
"305 Use Proxy",
"306 unused",
"307 Temporary Redirect",
"400 Bad Request",
"401 Authorization Required",
"402 Payment Required",
"403 Forbidden",
"404 Not Found",
"405 Method Not Allowed",
"406 Not Acceptable",
"407 Proxy Authentication Required",
"408 Request Time-out",
"409 Conflict",
"410 Gone",
"411 Length Required",
"412 Precondition Failed",
"413 Request Entity Too Large",
"414 Request-URI Too Large",
"415 Unsupported Media Type",
"416 Requested Range Not Satisfiable",
"417 Expectation Failed",
"418 unused",
"419 unused",
"420 unused",
"421 unused",
"422 Unprocessable Entity",
"423 Locked",
"424 Failed Dependency",
"425 No code",
"426 Upgrade Required",
"500 Internal Server Error",
"501 Method Not Implemented",
"502 Bad Gateway",
"503 Service Temporarily Unavailable",
"504 Gateway Time-out",
"505 HTTP Version Not Supported",
"506 Variant Also Negotiates",
"507 Insufficient Storage",
"508 unused",
"509 unused",
"510 Not Extended"

IANA HTTP Status Code Registry

WordPress 2.8 Changes

I just learned that my modification to the WordPress core was accepted and will be implemented for version 2.8! This may mean WordPress is the only 100% HTTP/1.1 compliant software on the net! Below is the new list (I thought someone out there could use the php array) and as you can see, unfortunately418 I'm a teapotdidn't make it ;)

$wp_header_to_desc = array(
  100 => 'Continue',
  101 => 'Switching Protocols',
  102 => 'Processing',
 
  200 => 'OK',
  201 => 'Created',
  202 => 'Accepted',
  203 => 'Non-Authoritative Information',
  204 => 'No Content',
  205 => 'Reset Content',
  206 => 'Partial Content',
  207 => 'Multi-Status',
  226 => 'IM Used',
 
  300 => 'Multiple Choices',
  301 => 'Moved Permanently',
  302 => 'Found',
  303 => 'See Other',
  304 => 'Not Modified',
  305 => 'Use Proxy',
  306 => 'Reserved',
  307 => 'Temporary Redirect',
 
  400 => 'Bad Request',
  401 => 'Unauthorized',
  402 => 'Payment Required',
  403 => 'Forbidden',
  404 => 'Not Found',
  405 => 'Method Not Allowed',
  406 => 'Not Acceptable',
  407 => 'Proxy Authentication Required',
  408 => 'Request Timeout',
  409 => 'Conflict',
  410 => 'Gone',
  411 => 'Length Required',
  412 => 'Precondition Failed',
  413 => 'Request Entity Too Large',
  414 => 'Request-URI Too Long',
  415 => 'Unsupported Media Type',
  416 => 'Requested Range Not Satisfiable',
  417 => 'Expectation Failed',
  422 => 'Unprocessable Entity',
  423 => 'Locked',
  424 => 'Failed Dependency',
  426 => 'Upgrade Required',
 
  500 => 'Internal Server Error',
  501 => 'Not Implemented',
  502 => 'Bad Gateway',
  503 => 'Service Unavailable',
  504 => 'Gateway Timeout',
  505 => 'HTTP Version Not Supported',
  506 => 'Variant Also Negotiates',
  507 => 'Insufficient Storage',
  510 => 'Not Extended'
);

RIPE WHOIS

All the status codes are standard HTTP codes ( http://www.iana.org/assignments/http-status-codes ).

Clients should avoid any form of coupling with the the text/plain error message contained in response body since it may change between different releases of the API and is only intended as a starting point for indentifying the real causes of the exception event.

The following table gives a brief description of the mapping between standard Whois V.3 responses and the related REST services status codes. Consider this table as just an example of the error mapping strategy, it may change with future releases.

Clients will have to define error messages generic enough to represent the four main error conditions, that are Bad Request, Forbidden, Not Found and Internal Server Error.

For example a possible mapping for client side error messages may be:

Helpful HTTP Links

1. IANA registry
2. Hyper Text Coffee Pot Control Protocol (HTCPCP/1.0)
3. Adobe Flash status code definitions (ie 408)
4. Microsoft Internet Information Server Status Codes and Sub-Codes
5. httplint
6. HTTP Headers, brief intro.
7. Common User-Agent Issues
8. [RFC2295] Holtman, K. and A.H. Mutz , " Transparent Content Negotiation in HTTP ", RFC 2295, March 1998.
9. [RFC2518] Goland, Y. , Whitehead, E. , Faizi, A. , Carter, S.R. , and D. Jensen , " HTTP Extensions for Distributed Authoring -- WEBDAV ", RFC 2518, February 1999.
10. [RFC2616] Fielding, R. , Gettys, J. , Mogul, J. , Frystyk, H. , Masinter, L. , Leach, P. , and T. Berners-Lee , " Hypertext Transfer Protocol -- HTTP/1.1 ", RFC 2616, June 1999.
11. [RFC2774] Nielsen, H. , Leach, P. , and S. Lawrence , " An HTTP Extension Framework ", RFC 2774, February 2000.
12. [RFC2817] Khare, R. and S. Lawrence, " Upgrading to TLS Within HTTP/1.1 ", RFC 2817, May 2000.
13. [RFC3229] Mogul, J., Krishnamurthy, B., Douglis, F., Feldmann, A., Goland, Y., van Hoff, A., and D. Hellerstein, " Delta encoding in HTTP ", RFC 3229, January 2002.
14. [RFC4918] Dusseault, L., Ed. , " HTTP Extensions for Web Distributed Authoring and Versioning (WebDAV) ", RFC 4918, June 2007.

HTTP Status Codes and Htaccess ErrorDocuments originally appeared on AskApache.com

The php part of this article is based on my Advanced WordPress 404.php article from 2008. Many of the following ideas came out of the research performed to enumerate every single Apache ErrorDocument, including learning how to view the defaults and many cool tricks for htaccess.

The PHP HTTP ErrorDocument Handler

Just save this as /err.php or whatever. The best is to put it in a cgi-bin script-alias directory under your DOCUMENT_ROOT like /cgi-bin/e.php but most people don't know how. That way you can setup some advanced stuff in a /cgi-bin/.htaccess file. If you are interested in locking it down, I recommend reading Securing php.ini and php-cgi with .htaccess.

Advantages and Reasons for Using

Fast, HTTP Protocol Compliance, protection. If you are reading this article, you already know and just want to check out the code!

<?php
ob_start();
@set_time_limit(5);
@ini_set('memory_limit', '64M');
@ini_set('display_errors', 'Off');
error_reporting(0);
 
function print_error_page()
{
 
  $status_reason = array(
  100 => 'Continue',
  101 => 'Switching Protocols',
  102 => 'Processing',
  200 => 'OK',
  201 => 'Created',
  202 => 'Accepted',
  203 => 'Non-Authoritative Information',
  204 => 'No Content',
  205 => 'Reset Content',
  206 => 'Partial Content',
  207 => 'Multi-Status',
  226 => 'IM Used',
  300 => 'Multiple Choices',
  301 => 'Moved Permanently',
  302 => 'Found',
  303 => 'See Other',
  304 => 'Not Modified',
  305 => 'Use Proxy',
  306 => 'Reserved',
  307 => 'Temporary Redirect',
  400 => 'Bad Request',
  401 => 'Unauthorized',
  402 => 'Payment Required',
  403 => 'Forbidden',
  404 => 'Not Found',
  405 => 'Method Not Allowed',
  406 => 'Not Acceptable',
  407 => 'Proxy Authentication Required',
  408 => 'Request Timeout',
  409 => 'Conflict',
  410 => 'Gone',
  411 => 'Length Required',
  412 => 'Precondition Failed',
  413 => 'Request Entity Too Large',
  414 => 'Request-URI Too Long',
  415 => 'Unsupported Media Type',
  416 => 'Requested Range Not Satisfiable',
  417 => 'Expectation Failed',
  422 => 'Unprocessable Entity',
  423 => 'Locked',
  424 => 'Failed Dependency',
  426 => 'Upgrade Required',
  500 => 'Internal Server Error',
  501 => 'Not Implemented',
  502 => 'Bad Gateway',
  503 => 'Service Unavailable',
  504 => 'Gateway Timeout',
  505 => 'HTTP Version Not Supported',
  506 => 'Variant Also Negotiates',
  507 => 'Insufficient Storage',
  510 => 'Not Extended'
  );
 
  $status_msg = array(
  400 => "Your browser sent a request that this server could not understand.",
  401 => "This server could not verify that you are authorized to access the document requested.",
  402 => 'The server encountered an internal error or misconfiguration and was unable to complete your request.',
  403 => "You don't have permission to access %U% on this server.",
  404 => "We couldn't find <acronym title='%U%'>that uri</acronym> on our server, though it's most certainly not your fault.",
  405 => "The requested method is not allowed for the URL %U%.",
  406 => "An appropriate representation of the requested resource %U% could not be found on this server.",
  407 => "An appropriate representation of the requested resource %U% could not be found on this server.",
  408 => "Server timeout waiting for the HTTP request from the client.",
  409 => 'The server encountered an internal error or misconfiguration and was unable to complete your request.',
  410 => "The requested resource %U% is no longer available on this server and there is no forwarding address. Please remove all references to this resource.",
  411 => "A request of the requested method GET requires a valid Content-length.",
  412 => "The precondition on the request for the URL %U% evaluated to false.",
  413 => "The requested resource %U% does not allow request data with GET requests, or the amount of data provided in the request exceeds the capacity limit.",
  414 => "The requested URL's length exceeds the capacity limit for this server.",
  415 => "The supplied request data is not in a format acceptable for processing by this resource.",
  416 => 'Requested Range Not Satisfiable',
  417 => "The expectation given in the Expect request-header field could not be met by this server. The client sent <code>Expect:</code>",
  422 => "The server understands the media type of the request entity, but was unable to process the contained instructions.",
  423 => "The requested resource is currently locked. The lock must be released or proper identification given before the method can be applied.",
  424 => "The method could not be performed on the resource because the requested action depended on another action and that other action failed.",
  425 => 'The server encountered an internal error or misconfiguration and was unable to complete your request.',
  426 => "The requested resource can only be retrieved using SSL. Either upgrade your client, or try requesting the page using https://",
  500 => 'The server encountered an internal error or misconfiguration and was unable to complete your request.',
  501 => "This type of request method to %U% is not supported.",
  502 => "The proxy server received an invalid response from an upstream server.",
  503 => "The server is temporarily unable to service your request due to maintenance downtime or capacity problems. Please try again later.",
  504 => "The proxy server did not receive a timely response from the upstream server.",
  505 => 'The server encountered an internal error or misconfiguration and was unable to complete your request.',
  506 => "A variant for the requested resource <code>%U%</code> is itself a negotiable resource. This indicates a configuration error.",
  507 => "The method could not be performed.  There is insufficient free space left in your storage allocation.",
  510 => "A mandatory extension policy in the request is not accepted by the server for this resource."
  );
 
  // Get the Status Code
  if (isset($_SERVER['REDIRECT_STATUS']) && ($_SERVER['REDIRECT_STATUS'] != 200))$sc = $_SERVER['REDIRECT_STATUS'];
  elseif (isset($_SERVER['REDIRECT_REDIRECT_STATUS']) && ($_SERVER['REDIRECT_REDIRECT_STATUS'] != 200)) $sc = $_SERVER['REDIRECT_REDIRECT_STATUS'];
  $sc = (!isset($_GET['error']) ? 404 : $_GET['error']);
 
  $sc=abs(intval($sc));
 
  // Redirect to server home if called directly or if status is under 400
  if( ( (isset($_SERVER['REDIRECT_STATUS']) && $_SERVER['REDIRECT_STATUS'] == 200) && (floor($sc / 100) == 3) )
     || (!isset($_GET['error']) && $_SERVER['REDIRECT_STATUS'] == 200)  )
  {
      @header("Location: http://{$_SERVER['SERVER_NAME']}",1,302);
      die();
  }
 
  // Check range of code or issue 500
  if (($sc < 200) || ($sc > 599)) $sc = 500;
 
  // Check for valid protocols or else issue 505
  if (!in_array($_SERVER["SERVER_PROTOCOL"], array('HTTP/1.0','HTTP/1.1','HTTP/0.9'))) $sc = 505;
 
  // Get the status reason
  $reason = (isset($status_reason[$sc]) ? $status_reason[$sc] : '');
 
  // Get the status message
  $msg = (isset($status_msg[$sc]) ? str_replace('%U%', htmlspecialchars(strip_tags(stripslashes($_SERVER['REQUEST_URI']))), $status_msg[$sc]) : 'Error');
 
  // issue optimized headers (optimized for your server)
  @header("{$_SERVER['SERVER_PROTOCOL']} {$sc} {$reason}", 1, $sc);
  if( @php_sapi_name() != 'cgi-fcgi' ) @header("Status: {$sc} {$reason}", 1, $sc);
 
  // A very small footprint for certain types of 4xx class errors and all 5xx class errors
  if (in_array($sc, array(400, 403, 405)) || (floor($sc / 100) == 5))
  {
    @header("Connection: close", 1);
    if ($sc == 405) @header('Allow: GET,HEAD,POST,OPTIONS', 1, 405);
  }
 
  echo "<!DOCTYPE HTML PUBLIC \"-//IETF//DTD HTML 2.0//EN\">\n<html>";
  echo "<head>\n<title>{$sc} {$reason}</title>\n<h1>{$reason}</h1>\n<p>{$msg}<br />\n</p>\n";
}
 
function askapache_global_debug()
{
  # http://www.php.net/manual/en/function.array-walk.php#100681
  global $_GET,$_POST,$_ENV,$_SERVER;  $g=array('_ENV','_SERVER','_GET','_POST');
  array_walk_recursive($g, create_function('$n','global $$n;if( !!$$n&&ob_start()&&(print "[ $"."$n ]\n")&&array_walk($$n,
    create_function(\'$v,$k\', \'echo "[$k] => $v\n";\'))) echo "<"."p"."r"."e>".htmlspecialchars(ob_get_clean())."<"."/"."pr"."e>";') );
}
 
print_error_page();
//if($_SERVER['REMOTE_ADDR']=='youripaddress')askapache_global_debug();
echo "</body>\n</html>";
echo ob_get_clean();
exit;
?>

Note: If you are installing this on a non-linux/non-apache machine/server, you will need to read your products documentation for custom error documents. It will work on any machine that can run php.

Htaccess ErrorDocument Tips

The thing is, how do you setup your website to use this php file to be able to handle all those HTTP Status Codes gracefully? You just need to configure your server to use that php file for any Status Codes you want. If you are building an ErrorDocument handling system for a server-wide, multi-site, setup, you will want to instead use the method I use. Instead of using a separate language like PHP, Python, Ruby, Perl, etc, to handle errors, I rely on the very safe and fast SSI method. I detailed the advanced ErrorDocument SSI (.htaccess or httpd.conf)..

If you instead like most of us, you will be setting this up for 1 site, or 1 DOCUMENT_ROOT serving virtual hosts. For that the best method is to modify your .htaccess file.

Using Redirect in .htaccess to trigger Errors

This is one of my all time favorite discoveries from my apache studies. It's documented elsewhere on this site, but if you want to test it out, just request www.askapache.com/show-error-402. Of course the error handling that I have in place is quite nice.

Redirect 400 /show-error-400
Redirect 401 /show-error-401
Redirect 402 /show-error-402
Redirect 403 /show-error-403
Redirect 405 /show-error-405
Redirect 406 /show-error-406
Redirect 407 /show-error-407
Redirect 408 /show-error-408
Redirect 409 /show-error-409
Redirect 410 /show-error-410
Redirect 411 /show-error-411
Redirect 412 /show-error-412
Redirect 413 /show-error-413
Redirect 414 /show-error-414
Redirect 415 /show-error-415
Redirect 416 /show-error-416
Redirect 417 /show-error-417
Redirect 418 /show-error-418
Redirect 419 /show-error-419
Redirect 420 /show-error-420
Redirect 421 /show-error-421
Redirect 422 /show-error-422
Redirect 423 /show-error-423
Redirect 424 /show-error-424
Redirect 425 /show-error-425
Redirect 426 /show-error-426
Redirect 500 /show-error-500
Redirect 501 /show-error-501
Redirect 502 /show-error-502
Redirect 503 /show-error-503
Redirect 504 /show-error-504
Redirect 505 /show-error-505
Redirect 506 /show-error-506
Redirect 507 /show-error-507
Redirect 508 /show-error-508
Redirect 509 /show-error-509
Redirect 510 /show-error-510

Powerful Mod_Rewrite Trick

Here's how to combine the power of mod_rewrites ability to parse requests and environment variables with the above Redirect trick to trigger a specific ErrorDocument based on the query_string parameter error. This trick is only on AskApache.com, very powerful trick if you need to force ErrorDocuments.

RewriteCond %{QUERY_STRING} error=([4|5][0-9][0-9]) [NC]
RewriteCond %{QUERY_STRING} !404
RewriteRule . /show-error-%1 [L]

ErrorDocument Example for .htaccess

So if you save the php file as err.php in your DOCUMENT_ROOT, these are the htaccess commands that will enable its use.

The addition of the ?error=num should be unneccessary on a good linux machine, it's a way for lesser OS's and webhosts to still be able to use errordocuments. Basically Apache handles ErrorDocuments by setting special DEBUGGING variables (Start with REDIRECT_) so it's very easy to determine the STATUS CODE by just viewing $_SERVER['REDIRECT_STATUS']. If a recursive type of redirect is going on, you may see $_SERVER['REDIRECT_REDIRECT_STATUS']. Dumb (consistently) OS's like a Windows server almost always have problems with things like that, because they don't give a hoot about POSIX or standards, why should they when no one can view their code anyway. Here are some more details on the REDIRECT_STATUS and other ways to use these variables.

If you want to learn how to enumerate and view the different variables that are in your Apache environment, I think I have the best tutorial on the planet for how to do this with PHP and mod_rewrite with mod_headers. That article is the basis for anyone who is hired to do mod_rewrites on a new server without root access. I would say that one article will inform you more about mod_rewrite then any other article on this site.

###
# ErrorDocument: In the event of a problem or error, what the server will return to the client. URLs
# can begin with a / for local web-paths (relative to DocumentRoot), or be a full URL which the client
# can resolve. Alternatively, a message can be displayed.  If a malformed request is detected, normal
# request processing will be immediately halted and the internal error message returned.
#
# Prior to version 2.0, messages were indicated by prefixing them with a
# single unmatched double quote character.
#
# The special value default can be used to specify Apache's simple hardcoded message and
# will restore Apache's simple hardcoded message.
#
ErrorDocument 400 /err.php?error=400
ErrorDocument 401 /err.php?error=401
ErrorDocument 402 /err.php?error=402
ErrorDocument 403 /err.php?error=403
ErrorDocument 404 /err.php?error=404
ErrorDocument 405 /err.php?error=405
ErrorDocument 406 /err.php?error=406
ErrorDocument 407 /err.php?error=407
ErrorDocument 408 /err.php?error=408
ErrorDocument 409 /err.php?error=409
ErrorDocument 410 /err.php?error=410
ErrorDocument 411 /err.php?error=411
ErrorDocument 412 /err.php?error=412
ErrorDocument 413 /err.php?error=413
ErrorDocument 414 /err.php?error=414
ErrorDocument 415 /err.php?error=415
ErrorDocument 416 /err.php?error=416
ErrorDocument 417 /err.php?error=417
ErrorDocument 422 /err.php?error=422
ErrorDocument 423 /err.php?error=423
ErrorDocument 424 /err.php?error=424
ErrorDocument 426 /err.php?error=426
ErrorDocument 500 /err.php?error=500
ErrorDocument 501 /err.php?error=501
ErrorDocument 502 /err.php?error=502
ErrorDocument 503 /err.php?error=503
ErrorDocument 504 /err.php?error=504
ErrorDocument 505 /err.php?error=505
ErrorDocument 506 /err.php?error=506
ErrorDocument 507 /err.php?error=507
ErrorDocument 510 /err.php?error=510

PHP to handle HTTP Status Codes for ErrorDocument originally appeared on AskApache.com

I am almost ready to publish the final tutorial on using ssh tunnels from a truecrypt partition on a Windows machine. Of course I choose to go way overboard in my research and the tutorial is full of some pretty awesome windows tricks.. I will come back to this post soon and post all the other advanced tools I use for debugging windows, for now though you MUST know how to debug the kernel and use these basic debugging tools.

Debugging Tools for Windows

Target Computer and Host Computer

Kernel-mode debugging requires a target computer and a host computer. The target computer is used to run the kernel-mode application. The host computer is used to run the debugger. The following diagram shows the typical Microsoft Windows setup that you can use to perform kernel debugging and diagnose system failures. Typical Windows debugging setup This diagram shows the typical setup. However, the current versions of KD and WinDbg (which you installed with this documentation) are flexible. KD and WinDbg can do the following

• Debug a target computer that is running Windows.
• Debug a target computer that is running on an x86-based platform, an Itanium-based platform, or an x64-based platform.
• Can be started from a host computer that is running Windows.
• Can be started from a host computer that is on an x86-based platform, an Itanium-based platform, or an x64-based platform.

The target computer and host computer do not have to use the same platform or the same version of Windows. Kernel debugging does not require specific combinations of the free or checked builds. You can debug a free system from a free or checked system, and you can debug a checked system from a free or checked system. However, typically, there is no reason for the host computer to run the slower checked build. Note If you are running the debuggers from an Itanium-based host computer, make sure that you are using the correct version of the binaries. For more information about which version of the debugger package to use, see Choosing a 32-bit or 64-bit Debugger Package.

Debuggers

WinDbg  (Windbg.exe)

A user-mode and kernel-mode debugger with a graphical interface.

KD  (Kd.exe)

A kernel-mode debugger with a console interface.

CDB  (Cdb.exe)

A user-mode debugger with a console interface.

NTSD  (Ntsd.exe)

A user-mode debugger with a console interface. CDB and NTSD are virtually identical. In this documentation, whenever a reference is made to "CDB", it applies to both CDB and NTSD. When these two debuggers differ, it is noted. (See CDB and NTSD for details.)

Using Debugging Tools for Windows Download Windows Symbol Packages Symbol packages for a variety of Windows versions. Install Debugging Tools for Windows 32-bit Version Download page for the latest 32-bit packages. Install Debugging Tools for Windows 64-bit Versions Download page for the latest 64-bit packages. What's New for Debugging Tools for Windows Debugging Tools and Symbols: Getting Started Tips for using Debugging Tools for Windows, with links to presentations and papers on best practices Debugger How-Tos Driver Tip: Debugging Windows Vista Improve Driver Debugability 1394 Kernel Debugging Tips and Tricks [WinHEC 2004; 373 KB] Advanced Driver Debugging [336 KB] Driver Debugging Basics [WinHEC 2007; 633 KB] Debugging Kernel-Mode Driver Framework Drivers Debugging User-Mode Driver Framework Drivers Training Sessions Debugging Tools for Windows (MSDN) HOWTO: Enable Verbose Debug Tracing in Various Drivers and Subsystems (314743) WDK Online: Tools for Debugging Drivers Resources WDK Documentation Download Driver Developer Community Resources Driver Signing Requirements for Windows Notes from Windows Development Teams Support for Developer Kits and Tools Driver Developer Blogs Windows Driver Kit (WDK) Version 7.1.0 Release Notes WDK Documentation on MSDN See Also Microsoft Application Verifier

Additional Tools and Utilities

Logger  (Logger.exe and Logexts.dll)

A tool and an extension DLL that record the function calls and other actions of a program. Logger is described in this documentation; see Logger and LogViewer.

LogViewer  (Logviewer.exe)

A tool that displays the logs created by Logger. LogViewer is described in this documentation; see Logger and LogViewer.

ADPlus  (Autodump+, Adplus.vbs)

A console-based Microsoft Visual Basic script that can automatically create memory dump files and log files with debug output from one or more processes. ADPlus is described in this documentation; see ADPlus.

DbgRpc  (Dbgrpc.exe)

A tool used to display Microsoft Remote Procedure Call (RPC) state information. DbgRpc is described in this documentation; see RPC Debugging and Using the DbgRpc Tool.

KDbgCtrl  (Kernel Debugging Control, Kdbgctrl.exe)

A tool that controls and configures the kernel debugging connection. KDbgCtrl is described in this documentation; see Using KDbgCtrl.

SrcSrv  (Srcsrv.dll)

A source server that can be used to deliver source files while debugging. SrcSrv is described in this documentation; see SrcSrv.

SymSrv  (Symsrv.dll)

A symbol server that the debugger can use to connect to a symbol store. SymSrv is described in this documentation; see SymSrv.

SymStore  (Symstore.exe)

A tool used to create a symbol store. SymSrv is described in this documentation; see Using SymStore.

SymProxy

A tool used to create a single HTTP symbol server on your network that all your debuggers can point to. This has the benefit of pointing to multiple symbol servers (both internal and external) with a single symbol path, handling all authentication, and increasing performance via symbol caching. SymProxy is described in this documentation; see SymProxy.

AgeStore  (Agestore.exe)

A tool that removes old entries in the downstream store of a symbol server or a source server. AgeStore is described in this documentation; see AgeStore.

DBH  (Dbh.exe)

A tool that displays information about the contents of a symbol file. DBH is described in this documentation; see DBH.

PDBCopy  (Pdbcopy.exe)

A tool that removes private symbol information from a symbol file, and controls which public symbols are included in the file. PDBCopy is described in this documentation; see PDBCopy.

DumpChk  (Dump File Checking Utility, Dumpchk.exe)

A tool used to validate a memory dump file. DumpChk is described in this documentation; see DumpChk.

DbgSrv  (Dbgsrv.exe)

A process server used for remote debugging. DbgSrv is described in this documentation; see Process Servers (User Mode).

KdSrv  (Kdsrv.exe)

A KD connection server used for remote debugging. KDSrv is described in this documentation; see KD Connection Servers (Kernel Mode).

DbEngPrx  (Dbengprx.exe)

A repeater (small proxy server) used for remote debugging. DbgSrv is described in this documentation; see Repeaters.

The Remote tool  (Remote.exe)

A remoting tool that can be used to remotely control any console program, including KD, CDB, and NTSD. The Remote tool is described in this documentation; see Remote Tool and Remote Debugging Through Remote.exe.

GFlags  (Global Flags Editor, Gflags.exe)

A tool used to control registry keys and other settings. GFlags is described in this documentation; see GFlags.

The Kill tool  (Kill.exe)

A tool used to terminate a process. The Kill tool is described in this documentation; see Kill Tool.

The Breakin tool  (Breakin.exe)

A tool used to cause a user-mode break to occur in a process. Breakin.exe is not described in this documentation. Use the breakin /? command for help with this tool.

The List tool  (File List Utilit y, List.exe)

List.exe is not described in this documentation. Use the list /? command for help with this tool.

TList  (Task List Viewer, Tlist.exe)

A tool used to list all running processes. TList is described in this documentation; see TList.

RTList  (Remote Task List Viewer, Rtlist.exe)

A tool used to list running processes via a DbgSrv process server. RTList is not described in this documentation. Use the rtlist /? command for help with this tool.

UMDH  (User-Mode Dump Heap utility, Umdh.exe)

A tool used to analyze heap allocations. UMDH is described in this documentation; see UMDH.

USBView  (Universal Serial Bus Viewer, Usbview.exe)

A tool used to display the USB devices connected to a computer. USBView is described in this documentation; see USBView.

Documentation

"Debugging Tools for Windows"  (Debugger.chm)

This is the documentation you are currently reading. It is the central documentation for Debugging Tools for Windows.

"Debug Help Library"  (Dbghelp.chm)

This documentation describes the DbgHelp API and the ImageHlp API, and also explains how to create your own symbol server. This is installed when you peform a custom install of Debugging Tools for Windows and select the SDK feature and its subfeatures.

Tools Outside the Debugging Tools for Windows Package

Dr. Watson  (Drwtsn32.exe)

A tool used for automatically creating dump files and sending error reports to Microsoft Online Crash Analysis (OCA). Dr. Watson is partially described in this documentation; see Dr. Watson. The other features of Dr. Watson are described in the help file associated with drwtsn32.exe.

Build utility  (Build.exe)

A compiler and linker used to build debugger extensions and other programs. The Build utility and its documentation can be found in the Windows Driver Kit, and in earlier versions of the Windows DDK.

BinPlace  (Binplace.exe)

A tool used to control symbol files for build products. BinPlace and its documentation can be found in the Windows Driver Kit, and in earlier versions of the Windows DDK.

Application Verifier  (AppVerif.exe and !avrf)

A tool used to test user-mode applications. This tool consists of two components: the AppVerif.exe utility and the !avrf extension command. All the features of Application Verifier that are debugger-related are described in Application Verifier. The other features of Application Verifier are described in the help file associated with AppVerif.exe.

Debugging different target platforms

CDB

NTSD

NTSD in the System32 Directory

• This version of NTSD cannot be used for Remote Debugging Through the Debugger.
• This version of NTSD may not match the version of the documentation you are currently reading.

Controlling CDB or NTSD from the Kernel Debugger

Debugging Tools for Windows originally appeared on AskApache.com