Comments on: How to enable port 587 (submission) in postfix

By: Joseph

Joseph — Wed, 10 Apr 2013 05:08:21 +0000

Just wondering if its possible to restrict all out-going mails to port 587 and NOT allow any sending out of emails on port 25.

Port 25 should only be used to receive mail and NOT send out …How can I do this?

By: Chandan

Chandan — Thu, 14 Mar 2013 19:06:08 +0000

Cool….Simply awesome!!!

By: Boyan Alexiev

Boyan Alexiev — Mon, 17 Sep 2012 17:11:34 +0000

Dear Dylan,

nice note about the TLS. However not only the milter line depends on the specific configuration, but all lines, and they also should exist in the version of postifx that is used. For example, another possible option is “-o smtpd_enforce_tls=yes”, but it may be deprecated (haven’t checked so far).

As for the SSL and port, please note that port 465 is deprecated for SMTPS and is no longer RFC-compliant. This port is already assigned for different purposes. Wiki provides more info, you can also check the RFC. Hope this helps.
http://en.wikipedia.org/wiki/SMTPS

By: Dylan Myers

Dylan Myers — Sun, 12 Aug 2012 01:29:15 +0000

You guys are all missing something very important here. “Submission” isn’t meant to be a straight copy of the plain auth port 25. Its meant to be encrypted. This is a ‘correct’ “Submission” entry in master.cf:

submission inet n – n – – smtpd
-o smtpd_tls_security_level=encrypt
-o smtpd_sasl_auth_enable=yes
-o smtpd_client_restrictions=permit_sasl_authenticated,reject
-o milter_macro_daemon_name=ORIGINATING

The milter macro line isn’t needed in all configs, you should know what you’re doing before you rock and roll.

IMO you should probably not be using port 25 OR port 587. You should be using SSL (465), which is properly configured like this:

smtps inet n – n – – smtpd
-o smtpd_tls_wrappermode=yes
-o smtpd_sasl_auth_enable=yes
-o smtpd_client_restrictions=permit_sasl_authenticated,reject
-o milter_macro_daemon_name=ORIGINATING

And is what I actually am using on my production server.

By: Samuel Peixoto

Samuel Peixoto — Wed, 30 May 2012 19:36:47 +0000

Show!!!

Simple and objective.

By: Mark

Mark — Sun, 05 Feb 2012 04:35:58 +0000

Great post. I have been trying to get my postfix server to accept email from external authenticated clients on both port 25 and 587 for days, and haven’t been able to get it to work. I uncommented the submission line in master.cf, and opened up port 587 on my amazon server, and it worked! If only I had found this earlier. Thanks.

By: Rob

Rob — Mon, 21 Feb 2011 12:50:40 +0000

That is not true And Would not add a benefit

By: gboule35

gboule35 — Fri, 18 Feb 2011 08:40:13 +0000

you must also create an iptables prerouting for redirect inbound port 25 to port 587.

By: B. Davies

B. Davies — Tue, 01 Feb 2011 12:55:36 +0000

It should work – I think , just punch in port 587 and voilla !!

By: Robbert

Robbert — Wed, 05 Jan 2011 20:56:39 +0000

Make sure you enable this port in your firewall settings in ISPCONFIG3 aswell. Otherwise it wont work.