Search For If-Modified-Since

HTTP Status Codes and Htaccess ErrorDocuments

There are a total of 57 HTTP Status Codes recognized by the Apache Web Server. Wouldn't you like to see what all those headers and their output, ErrorDocuments look like?

Posted in Htaccess | Published on January 4, 2011 |23 Comments »

Ultimate Htaccess Part II

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.

Posted in Htaccess | Published on October 16, 2010 |5 Comments »

mod_rewrite Fix for Caching Updated Files

Web Developers sometimes use file.ext?v=004 as a version control system to force visitors to use updated files. This is terrible. Instead link to apache-003.css and set it to be cached forever. When you change the file you just change the links to apache-004.css. That eliminates millions of bandwidth and resource robbing If-Modified-Since requests. You only need Apache with mod_rewrite, and 1-10 minutes!

Posted in Htaccess | Published on August 30, 2009 |3 Comments »

THE Ultimate Htaccess

Skip this - still under edit

I discovered these tips and tricks mostly while working as a network security penetration specialist hired to find security holes in web hosting environments. Shared hosting is the most common and cheapest form of web-hosting where multiple customers are placed on a single machine and "share" the resources (CPU/RAM/SPACE). The machines are configured to basically ONLY do HTTP and FTP. No shells or any interactive logins, no ssh, just FTP access. That is when I started examining htaccess files in great detail and learned about the incredible untapped power of htaccess. For 99% of the worlds best Apache admins, they don't use .htaccess much, if AT ALL. It's much easier, safer, and faster to configure Apache using the httpd.conf file instead. However, this file is almost never readable on shared-hosts, and I've never seen it writable. So the only avenue left for those on shared-hosting was and is the .htaccess file, and holy freaking fiber-optics.. it's almost as powerful as httpd.conf itself!

Most all .htaccess code works in the httpd.conf file, but not all httpd.conf code works in .htaccess files, around 50%. So all the best Apache admins and programmers never used .htaccess files. There was no incentive for those with access to httpd.conf to use htaccess, and the gap grew. It's common to see "computer gurus" on forums and mailing lists rail against all uses and users of .htaccess files, smugly announcing the well known problems with .htaccess files compared with httpd.conf - I wonder if these "gurus" know the history of the htaccess file, like it's use in the earliest versions of the HTTP Server- NCSA's HTTPd, which BTW, became known as Apache HTTP. So you could easily say that htaccess files predates Apache itself.

Once I discovered what .htaccess files could do towards helping me enumerate and exploit security vulnerabilities even on big shared-hosts I focused all my research into .htaccess files, meaning I was reading the venerable Apache HTTP Source code 24/7! I compiled every released version of the Apache Web Server, ever, even NCSA's, and focused on enumerating the most powerful htaccess directives. Good times! Because my focus was on protocol/file/network vulnerabilites instead of web dev I built up a nice toolbox of htaccess tricks to do unusual things. When I switched over to webdev in 2005 I started using htaccess for websites, not research. I documented most of my favorites and rewrote the htaccess guide for webdevelopers. After some great encouragement on various forums and nets I decided to start a blog to share my work with everyone, AskApache.com was registered, I published my guide, and it was quickly plagiarized and scraped all over the net. Information is freedom, and freedom is information, so this blog has the least restrictive copyright for you. Feel free to modify, copy, republish, sell, or use anything on this site ;)

Posted in Htaccess | Published on January 10, 2009 |87 Comments »

Htaccess SetEnvIf and SetEnvIfNoCase Examples

SetEnv, SetEnvIf, and SetEnvIfNoCase directives conditionally set environment variables accessible by scripts and apache based on HTTP Headers, Variables, and Request information.

• Unique mod_setenvif Variables
• Populates HTTP_MY_ Variables with mod_setenvif variable values
• Set REMOTE_HOST to HTTP_HOST
• Allows only if HOST Header is present in request
• Add values from HTTP Headers
• Set the REDIRECT_STATUS for Interpreter Security

Posted in Htaccess | Published on December 7, 2008 |7 Comments »

Speed Tips: Remove Last-Modified Header

If you remove the Last-Modified and ETag header, you will totally eliminate If-Modified-Since and If-None-Match requests and their 304 Not Modified Responses.

Posted in Htaccess | Published on September 10, 2007 |12 Comments »

Speed Tips: Turn Off ETags

By removing the ETag header, you disable caches and browsers from being able to validate files, so they are forced to rely on your Cache-Control and Expires header.

Posted in Htaccess | Published on |11 Comments »

Speed Up Sites with htaccess Caching

2 awesome ways to implement caching on your website using Apache .htaccess or httpd.conf. Both methods are extremely simple to set up and will dramatically speed up your site!

Posted in Htaccess | Published on December 5, 2006 |22 Comments »