Topic: e-smith as emailserver in nat lan

[oivvio polite]

This is my setup


  dsl to internet
      |
   eth0 (static public ip)
      |
nat firewall
      |   eth1
      |
 lan with private addresses
userboxes and e-smith box.

All users use SMTP server of DSL provider. No problem.
Most user get POP mail from other ISPs. No problem.
A couple of users want to have mail sent to their accounts on the e-smith box. I guess that I have to portforward som ports from the firewall to the e-smithserver. But which ones, 25 only, will this disrupt outgoing SMTP?

oivvio