[Mimedefang] OT: Blocking because of MX to 127.0.0.1

[Joseph Brennan]

> Our solution was to block incoming connections from 127.0.0.1 on the
> servers.  Is there ever a need to accept TCP connections from localhost
> for mail?


Yes.  That's how the sendmail daemon gets mail from local processes.

Even on our mail servers, we have cron jobs sending reports, so we
allow from localhost.  Some Mimedefang procedures send mail, if you
happen to use those, and forwarding with .procmailrc sends a new
message from localhost.

Joseph Brennan
Academic Technologies Group, Academic Information Systems (AcIS)
Columbia University in the City of New York