ISPConfig using iptables or on virtual machine?

[Showa]

Hello,

Is it possible to use iptables with ISPConfig 3?

I build a server with ISPConfig 3 according one of the howto's (Centos 5.5) for hosting websites.
Then I want to use the computer also as a samba server and a router for my private network. I used the howto Samba Domain Controller With LDAP Backend, and made some changes to the iptables for the router functions.

One functions with iptables on, and one with iptables off. What do I have to change in iptables to let ISPConfig function, or is it better to put both one seperate virtual machines?

Ad.