Ports allocation for ISPCP

[Nomis]

I have just completed Debian 4 installation and want to install ispCP on it. But before I do that I want to close all ports that are not needed.

I want the system to preform the following tasks.
Host Domains
Send and receive mail to these domains.
Allow the user to update his domain via FTP
Have remote access to there mail via a web interface
Load Spam Assassin and Anti virus.

So where can I get a list of ports that ispCP uses to perform these task's so that all unnecessary ports can be closed to prevent the system from attacks.

Thanking you in advance for your assistance.