Sendmail on ports 25 and 587


I like to use my Linode for outgoing mail but my ISP has started blocking port 25. No problem, I thought, I knew Sendmail could use an alternative so … in I removed the front dnl from the last line of this:

dnl # The following causes sendmail to additionally listen to port 587 for
dnl # mail from MUAs that authenticate. Roaming users who can't reach their
dnl # preferred sendmail daemon due to port 25 being blocked or redirected find
dnl # this useful.
dnl #
dnl DAEMON_OPTIONS(`Port=submission, Name=MSA, M=Ea')dnl

Recompiled, restarted Sendmail and all looks good when I telnet localhost 587. But … it stops responding to port 25 which is rather unhelpful. The word 'additionally' above suggests that it should do both.

Thanks for any help.



1 Reply


I had the same issue. It is easy enough to fix though. Just above the lines you quoted, you will see the (commented out) lines to listen on port 25 on the loopback interface ( I removed the address restriction and uncomment the line:

dnl # The following causes sendmail to only listen on the IPv4 loopback address

dnl # and not on any other network devices. Remove the loopback

dnl # address restriction to accept email from the internet or intranet.

dnl #

dnl # DAEMON_OPTIONS(`Port=smtp,Addr=, Name=MTA')dnl

DAEMON_OPTIONS(`Port=smtp, Name=MTA')dnl

Works like a charm for me



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