I need to setup Sendmail in my New Fedora Core 3. This Linux box is behind a Smoothwall Express Gateway to the world Just like other workstations in my organization. This is what I need this Linux comp to do:

1. I need it to relay mails from all workstations (relaying only)
2. I DONT want this server to relay mail from outside world.
3. I need this comp to reject infected mails and any spamming from within my LAN

What should be on my setup checklist? I have already downloaded the latest Sendmail release version. I understand Fedora comes with its own Sendmail version ( How do i updrade?).