Hi Harley,

Quote Originally Posted by x0500hl View Post
Postfix was not running. The Systems Admin I took this problem from said that postfix doesn't need to be running until this server is going to receive emails. I found that he was wrong about that. It appears that something was changed on the email reply server. Once it was pointed out that it wasn't a routing issue, the problem "miraculously" went away.
glad to see the problem got resolved that easily.

Technically speaking, the email infrastructure can actually be set up to have no Postfix running on individual servers, except for a central mail service machine. But in such a case, you need to point all mail clients to that central server for SMTP (see i. e. the definition for the "smtp" variable in "man 1 mailx"). By default, on a Linux machine, the clients will try to use contact the local MTA.