Apache Web Server Speed Configuration Hacks
Apache server performance can be improved by adding additional hardware resources such as RAM, faster CPU, etc.
Speed Up Sites with php Caching
This explains the basic methods to get started caching with php headers
Trace Email Back to the Sender
Locate the sender of an email and their geographical location, including messages sent through anonymous email services like Gmail, Yahoo, and Hotmail.
Top 5 Vulnerability Port Scanners
Asked some hackers and Computer Security gurus to list their 5 favorite Vulnerability/Port Scanners. Here are the results.
Debug apache log files from php
Secure phpinfo.php with .htaccess, Now instead of getting a 404 error you will see debug information which will help you find out what the problem is.
Using TIME_HOUR and TIME_MIN for htaccess RewriteCond
If you want to redirect to a different version of a file based on the time, this code is for you! Please read: Serve Alternate Content based on Time
Caching Tutorial for Webmasters
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).