This page last modified: Dec 08 2004
The problem is that email orginating on my machine is from localhost.localdomain, and not example.com (as it should be since we'll assume for this document that my host is example.com). Notice that the ctladdr and the from both say localhost.localdomain. The mail bounces from the recipient's host. Dec 8 09:32:34 example sendmail[4024]: iB6Jeqrn030992: to=<mst3k@someotherdomain.com>, ctladdr=<mst3k@localhost.localdomain> (501/501) , delay=1+18:51:42, xdelay=00:00:00, mailer=esmtp, pri=3900538, relay=mail.someotherdomain.com. [128.143.2.9], dsn=4.2.0, stat=Defer red: 450 <mst3k@localhost.localdomain>: Sender address rejected: Domain not found Dec 8 09:55:55 example sendmail[4083]: iB8EttLe004083: from=<mst3k@localhost.localdomain>, size=331, class=0, nrcpts=1, msgid=< 200412081455.iB8EttCd004080@localhost.localdomain>, proto=ESMTP, daemon=MTA, relay=localhost.localdomain [127.0.0.1] The problem was that example.com was in /etc/hosts incorrectly. The wrong entry: 127.0.0.1 localhost.localdomain localhost example.com example The correct entries: 127.0.0.1 localhost.localdomain localhost example.com 192.0.34.166 example.com example