Monitoring e-mails by TCP

[Rodrigo G. Tavares de Souza]

Hi,

  I'm very newbie  on freeBSD.
  I have already installed the Firewall(ipfw) + NAT, Squid + Sarg and 
Apache Http Server, and is working pretty well! :-)
  Now I have a need, and I don't know if I can do it with a  BSD solution!

  My e-mail server is outside of my network, is a comercial mail server.
  But, my e-mail trafic pass through a BSD server, the one I've 
mentioned before.

  So, what do I need to do?
  I need to make a copy of all received and delivered e-mail through my 
network!
  Is this possible? Is there a sofware (free or not), or a firewall 
configuration to do it?
  I think it would be a kind of TCP monitor on  ports 25 and 110, like 
some antivirus that scan e-mail trafic looking for virus!

  Any help is welcome!

Best regard for all.
Rodrigo Souza
Sao Paulo - Brazil