I'm trying to configure a few Fedora Core 5 computers to act as SMTP relay servers. However, I've never used Linux for that before, so I'm not sure where to start. My question is: what is the best (free) program to use as an SMTP relay, and how do I configure it to relay mail for only a few computers within a known IP range? Also, what is the easiest way to configure it to only allow SSH from a given IP and to block out all traffic not associated with SMTP (ie - SMTP and DNS)?
Thanks in advance!!!