I read about all those advanced DNS security features on a program called Simple DNS Plus it's only for windows:
DNS spoofing, Ignore UDP packets from port zero, Detect cloose telnet connections, Maximum simultaneous inbound TCP connections, Maximum recursive DNS requests to resolve simultaneously.
Are those functions enabled by default in ISPconfig installation?
Also, I'm using Centos 5.1 how do I update my machine with most current updates and should I do it because I read that certain updates can break ISPconfig functionality