Some idiot created a SSH worm that uses a dictionary attack to try to log into a computer over port 22. The worm tries to set up shop on your computer and tries to find the next vulnerable computer. This clogs up networks with bazillions of SSH login attempts.
Use mod_rewrite and .htaccess file to block user agent libwww-perl. Open your .htaccess file and add rule as follows:
Do the following:
1) Start Internet Information Services Manager or open the Internet Information Services (IIS) snap-in.
2) Expand Server_name, where Server_name is the name of the server, right-click Default SMTP Virtual Server, and then click Properties.
As By default Plesk administrator’s email address is listed in:
Focus: Linux, Apache 1.3+, [PHP], [MySQL]
Notes: Use at your own risk.
Summary
If you are reaching the limits of your server running Apache serving a lot of dynamic content, you can either spend thousands on new equipment or reduce bloat to increase your server capacity by anywhere from 2 to 10 times. This article concentrates on important and poorly-documented ways of increasing capacity without additional hardware.