This is basically just a holding spot for my SMTP server layout.
Port numbers have been changed to protect the innocent. :-)

Incoming Route
[Port 25]
[I'Net Gateway]
[Port 25]
[ASSP, on CentOS]
[Post 25]
[Trend Micro Interscan MSS on Win 2003]
[Port 25]
[Exchange 2003 on Win 2003]

Outgoing
[Client]
[Port 75]
[I'Net Gateway]
[Port 75]
[SMTP VirtServ1, Exchange 2003 on Win 2003]
[Port 55]
[ASSP, on CentOS]
[Port 45]
[SMTP VirtServ2, Exchange 2003 on Win 2003]
[Port 25]