Learning the Mac OS X Terminal, Part 2
Subject:   mail relay
Date:   2002-03-11 21:08:43
From:   magill
Response to: mail relay

If you do not have a valid IP address with a reverse lookup, the hostname will default to "localhost."

If you are running via NAT (behind an Airport Base,for example), you need to change "HOSTNAME" in the /etc/hostconfig file to be
the FQDN.

If you are working with a "normal" DHCP setup from some ISP, the usual problem is that they have not provided a reverse-lookup for your assigned address. Cable modem folks, and the RBOCs as DSL providers have a nasty habit of ignoring the reverse lookup entries for their addresses and it causes all kinds of agriation as a result.