The provided sendmail.mc file is used to enable ports 587/submission and/or 465/smtps. The problem is that enabling either one disables port 25/smtp.

I only have one server and would like to use it as MSA and MTA.

Traffic on 587 should be authenticated, on 25 should not.


See RFC 2476

  • The posted question is perfectly legitimate. There is a group of folks who are experts BUT when they find something they ignore, their reaction is to blame the victim and click the question down. StackExchange has found a mutually beneficial way to have these experts working for free. The payment is schadenfreude : they get to feel better by humiliating the users. – Travis Banger Nov 13 '16 at 15:44
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    1. SMTPS is deprecated. 2. SuperUser SE (or, possibly, ServerFault SE) is likely a better place to ask this kind of question. – countermode Nov 14 '16 at 8:35

Add the following lines to your sendmail.mc and generate new sendmail.cf

dnl Disable default MSA port support
dnl Modifiers=E - disable ETRN support
dnl Modifiers=a - require SMTP authentication
dnl Modifiers=s - provide smtps
DAEMON_OPTIONS(`Family=inet6, Name=MTA-v6, Port=smtp)dnl
DAEMON_OPTIONS(`Family=inet,  Name=MTA-v4, Port=smtp)dnl
DAEMON_OPTIONS(`Family=inet6, Name=MSP-v6, Port=submission, Modifiers=Ea)dnl
DAEMON_OPTIONS(`Family=inet,  Name=MSP-v4, Port=submission, Modifiers=Ea)dnl
DAEMON_OPTIONS(`Family=inet6, Name=SMTPS-v6, Port=smtps, Modifiers=Eas)dnl
DAEMON_OPTIONS(`Family=inet,  Name=SMTPS-v4, Port=smtps, Modifiers=Eas)dnl

If smtp (25), submission (587) or smtps (465) are not defined in you /etc/services file then use port numbers instead.

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