From: "Carlos E. R."
On 6/19/23 17:40, Carlos E. R. wrote:
On 2023-06-20 01:58, Marc Chamberlin via openSUSE Users wrote:
As always, thoughts and comments are much appreciated! Marc....
I'm confused.
I run the default postfix, which listens to port 25, and includes a sendmail binary, which can be called with no tricks to send mail.
No tricks at all.
Hi Carlos
"which listens to port 25" That's the problem with most MTA's, they listen on port 25 and I can't allow that.
Block it in the firewall.
That won't help; he wants another app to be able to listen on the port.
And probably listening on 25 can be disabled in postfix, but not
something I have investigated.
--
Cheers / Saludos,
Carlos E. R.
(from 15.4 x86_64 at Telcontar)
Yes; FTR, Postfix has a line in /etc/postfix/master.cf that looks like
this:
smtp inet n - n - - smtpd
Comment that out, restart the postfix daemon, and Postfix will no longer
monopolize port 25 (signified here by "smtp"). Alternatively, replacing
"smtp" by "localhost:10025" moves it out of the way by using a different
port on localhost.
================
From: "Dr. Werner Fink"
Block it in the firewall.
And probably listening on 25 can be disabled in postfix, but not something I have investigated.
If no sendmail daemon is running (aka stopped and disabled via systemctl) or if running but configured not to listen on port 25 aka smtp on 127.0.0.1 as well as on ::1 (change /etc/mail/linux.mc based on the README below /usr/share/sendmail/ and use the m4 command below /etc/mail/ to generate the /etc/sendmail.cf ) ... So far so good . . . but be aware that if no other daemon is listen on 127.0.0.1 as well as on ::1 at port 25 you'll get a connection refused . . . Werner In more detail, if sendmail is told to bind port 25 on localhost, Apache James will have to be told to bind port 25 on all interfaces *other than* localhost. Otherwise, it will try binding port 25 on 0.0.0.0, and this will fail, usually resulting in a complete failure of the MTA to start up. The error messages I've seen for this (and I've shot myself in this particular foot multiple times, not just with MTAs) are usually confusing, which I why I think this deserves special mention. -- Bob Rogers http://www.rgrjr.com/