A rip from two sites i guess.. http://www.configserver.com/cp/csf.html http://www.thealders.net/blogs/2007/01/17/server-hardening/ If you run your own Linux server here are some tips on server hardening, liberally stolen from the CFS security GUI script for cPanel/WHM, that I have become only too familiar with since yesterday: On your firewall (you do have one don’t you?) check the incoming MySQL port and if 3306 is open, close it. If this port is left open it can pose both a security and server abuse threat since not only can hackers attempt to break into MySQL, any user can host their SQL database on your server and access it from another host and so (ab)use your server resources Check /tmp permissions. /tmp should be chmod 1777 Check /tmp ownership /tmp should be owned by root:root Check /etc/cron.daily/logrotate for /tmp noexec workaround. Due to a bug in logrotate if /tmp is mounted with the noexec option, you need to have logrotate use a different temporary director...