Apache Security tips and tricks for securing Apache Web Servers using htaccess, httpd.conf, and other built-in techniques to thwart attackers. This really should be required reading for any Apache admin or user because these little tricks are so easy to do.
htaccess rewrite Master Class! If you understand the basics of mod_rewrite, or if you literally write the mod_rewite.c code, this article will transform your thinking. The transformation is profound. Deeply effective. Culmination of the best of the best mod_rewrite tricks for understanding and learning exactly what rewrite is doing.
The story behind this plugin is sorta wack, but in a good way :). While doing tons of security research on permissions, authorization, access, etc.. for the Password Protection plugin (still being worked on), I needed to have unheard of debugging capabilities while working on the plugin on the various websites, webhosts, and test servers that I use to test in different environments. So I hacked together a bunch of php code that helped me debug, actually I pretty much went overkill and tried to get as much debugging info as programmatically possible, and it ended up being so much code that I took it out of my Password Protection code and made it its own plugin.
What they say about kung-fu is true..
It can be attained by anyone through hard work over time. You can become as good as the amount of work you put in. Here's a short look at a basic technique that I use. Simply reverse engineering the source code and taking notes along the way...
static void php_session_send_cookie(TSRMLS_D)
if (SG(headers_sent)) {
if (output_start_filename) {
php_error_docref(NULL TSRMLS_CC, E_WARNING, "Cannot send session cookie - headers already sent by (output started at %s:%d)",
output_start_filename, output_start_lineno);
} else {
php_error_docref(NULL TSRMLS_CC, E_WARNING, "Cannot send session cookie - headers already sent");
}
return;
}
/* URL encode session_name and id because they might be user supplied */
e_session_name = php_url_encode(PS(session_name), strlen(PS(session_name)), NULL);
Ultimate Redirect Cheatsheet for multiple programming languages. Redirecting Users with Javascript redirect, meta refresh redirect, and php redirect, also htaccess methods, python, coldfusion, asp, perl, etc.
PHP's fsockopen function lets you open an Internet or Unix domain socket connection for connecting to a resource, and is one of the most powerful functions available in the php language.
We've figured out what mod_rewrite variables look like, a cheatsheet of the actual value.
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If you examine the preferences dialog of any modern Web browser (like Internet Explorer, Safari or Mozilla), you'll probably notice a 'cache' setting. This lets you set aside a section of your computer's hard disk to store representations that you've seen, just for you. The browser cache works according to fairly simple rules. It will check to make sure that the representations are fresh, usually once a session (that is, the once in the current invocation of the browser).
strace+ is an improved version of strace that collects stack traces associated with each system call. Since system calls require an expensive user-kernel context switch, they are often sources of performance bottlenecks. strace+ allows programmers to do more detailed system call profiling and determine, say, which call sites led to costly syscalls and thus have potential for optimization.
For the AskApache Google 404 WordPress Plugin update I added a new 404.php that is more advanced than anything previously seen for a 404.php
This is really useful for me because I work with dozens of different database servers. The first thing I do is run this command and paste it into the servers /etc/my.cnf file. That way I will always know the original value and it just makes life much easier.
$ mysql -NBe 'SHOW VARIABLES' |sed 's,\t,^=,'|column -ts^|tr "\n" '@'|eval $(echo "sed '" "s,@\("{a..z}"\),\n\n\1,;" "'")|tr '@' "\n"|sed 's,^,# ,g'
If for some reason you need to use windows .bat batch file scripting to do some task, or you just want to learn the most universal batch programming language on Windows machines, you lucked out and found the AskApache example. My expertise is the shell, in this article the shell is Windows cmd.exe. It has some pretty advanced windows shell usage, including pipes and redirection, but it's the modular linux-like coding approach that earns this script it's "advanced" title.
:SETPROMPT set PROMPT=$_[%USERNAME%@%USERDOMAIN%]$S[$P]$_$M$G && EXIT /B
My favorite tool (and I've tried sooo many) for editing most Windows files and especially .bat files is the free and open-source Notepad++. Set that up and you will have a color-syntax-highlighted editor for Batch Scripting that works very very well.
How I was able to preload many flash flv and swf files on one of my clients sites that has a lot of online video and relatively small traffic. Their site visitors would usually watch 3-10 videos per visit and so to make the videos load almost instantly on every page I came up with a way to preload the top 10 .flv files and the swf flv player files as soon as the visitor successfully started watching the 1st video. Of course I also setup .htaccess caching on the server so that once they downloaded the files into their cache they would never request them from the server again. I was having fun with this so its pretty funky and uses some really cool combinations of javascript, swf preloader from xml, css classes to help automate it all..
Top 3 ways to speed up websites that use Google Analytics. Host Script Locally, Fix Google-Analytics Cookie Domain, and Failsafe Loading for optimum tracking statistics.
Wanted to stick this here for a reference, mostly for me. I use ASCII alot in bash, preg_matches, preg_replace, etc..
SetEnv, SetEnvIf, and SetEnvIfNoCase directives conditionally set environment variables accessible by scripts and apache based on HTTP Headers, Variables, and Request information.
The goal is to add the HostGator server to be an exact mirror of the s.askapache.net domain, then to add that server as a 2nd A record to my DNS zone. That way half the visitors to the size will be taking up resources and bandwidth on the HostGator server instead of mine.
Round Robin A records in DNS are intended to evenly distribute queries between each host of the same name. Using some tricks straight out of a hackers toolbox we can verify if the distribution is taking place. (It is.)
Perhaps you want to keep status information between requests and use the URL to encode it. But you don't want to use a CGI wrapper for all pages just to strip out this information.
Sometimes there is an urgent need for creating an exact duplicate or "mirror" of a web site on a separate server. This could be needed for creating Round Robin Setups, Load-Balancing, Failovers, or for just plain vanilla backups. In the past I have used a lot of different methods to copy data from one server to another, including creating an archive of the whole directory and then using scp to send the file over, creating an archive and then encrypting it and then sending that file over using ftp, curl, etc., and my persistence at learning new ways to do things has paid off because now I use rsync to keep an exact replica of the entire directory on an external server, without having to use all the CPU and resources of other mirroring methods.
Comprehensive .htaccess example file with advanced examples in 1 htaccess sample skeleton .htaccess file with the very best apache htaccess examples... Updated frequently based on detailed info from the Apache htaccess tutorial.
3-Part article covering practical implementation of 3 advanced .htaccess features. Discover an easy way to boost your SEO the AskApache way (focus on visitors), a tip you might keep and use for life. Get some cool security tricks to use against spammers, crackers, and other nefarious sorts. Take your site's error handling to the next level, enhanced ErrorDocuments that go beyond 404's.
Unless you are a total linux-freak-guru like myself, and even if you are, it can be enormously challenging and somewhat overwhelming to locate and eliminate MySQL bottlenecks. While many DBAs focus on improving the performance of the queries themselves, this post will focus on the highest-impact items: MySQL Server Performance and OS Performance for MySQL. Specifically showing 4 awesome tools to auto-tune your MySQL and a few more tools just for monitoring!
Before
init-connect='SET NAMES utf8' init_connect='SET CHARACTER SET=utf-8'
After
init_connect='SET collation_connection = utf8_general_ci,NAMES utf8'
Here is even more information from the Ultimate Htaccess Part I. For now this is very rough and you will want to come back later to read it.
One of the biggest speed bottlenecks of sites today are images, specifically unoptimized images or large scaled images. With Apaches Rewrite module we can convert all existing jpegs and png files (and most gifs) to webp, then transparently rewrite them so that a request for img.png from a browser that supports webp will receive img.webp.
Nifty SEO tip to get Search Engine Bots to check your site every hour until you finish working on it and tell them you are finished.
The following is just a quick but detailed reference of some of the commands I used to successfully uninstall cpanel permanently. This is for advanced users of the shell. If you run a single one of these commands without fully understanding it, you will probably kill your server, lose everything on it permanently, not have a website or email for weeks.. So backup everything. FIRST. You should also contact your hosting provider support - but be prepared for some MAJOR negativity.. cpanel makes things very easy for web-hosting companies, and you are less than a drop in their bucket.
The Alexa Toolbar is a free search and navigation companion that accompanies you as you surf, providing useful information about the sites you visit without interrupting your Web browsing.