I am using sendmail, and it works happily with squirrelmail. The problem is that my HOSTNAME evironmental variable is www.example.xyz, not example.xyz. So it rejects all the mail that is sent to joe@example.xyz...

I can export the environmental variable and restart sendmail to get it to work, but after I restart it goes back to www.example.xyz!

I tried reconfiguring by going into netconfig, but it won't let me leave the 'hostname' blank.

I tried manually editing the /etc/HOSTNAME file, which causes apache to die when it starts up because it apparently needs a hostname.

Any Helpers?

What does the MX record for your domain look like?

its reaching the box, but its being denied. As for the mx records, I use dyndns.org. There aren't any mx records setup.