Recently I got chance to play with Virtuozzo VPS. Good news is they are good to reduced cost and bad news (as of Dec-04, 2004) they do not support full iptables rule set like –state and –log etc. After spending more than 4+ hrs I was able to setup simple but effective firewall on Red hat enterprise linux Virtuozzo VPS. Here is script. Make sure you customize it for your environment.
Xen is a free open source software virtual machine monitor for Intel / PowerPC architectures. It is software that runs on a host operating system and allows several guest operating systems to be run on top of the host on the same computer hardware at the same time (just like VMWare software). Luckily Installing and managing XEN is quite easy under CentOS 5 Linux.