Last year I implemented an ISPConfig3 configuration for personal use. Mainly to host some e-mail domains, and perhaps some basic websites. This setup relatively easy to implement a should have been a breeze to maintain.... Untill I got an email from the provider last Tuesday, mentioning that my Linux VPS was attacking other hosts around the world..... *GASP*.. my VPS had (most likely) been assimilated into a botnet of some sort, and it was flooding a ton of other hosts.