I'm writing with regard to the "most" frequently asked question at
sendmail.org :-) The one that says:
I'm getting these error messages:
553 MX list for domain.net points back to relay.domain.net
How can I solve this problem?
Sendmail (8.9.1) is functioning correctly for sending to any address except
domain.net to the w class both by the sendmail.cw file, and the Cw
definition in sendmail.cf, but no joy. (yes,
/usr/lib/mail/sh/check-hostname gets a valid result, and dns is ahead of
is only a problem if the message is initiated from the server itself. Sound
like a screwy rewriting rule or local mailer definition?
Any help would be appreciated... it's unbelievably frustrating when the faq
has a solution to your problem, but the solution doesn't work :-)
BTW - sendmail is not running as a daemon here, it's called explicitly by
software when an email is required to be sent. (and the SMTP port on the
server has a proprietary listener, but I don't think that's relevant)