On 2025-04-24, at 19:11 +0200, Wayne Spivak wrote:
I have 3 RPi using OpenSMTPD. These 3 RPi’s are only outgoing boxes
(system messages), they don’t receive email, nor do they have MX records.
The Pi’s are named NAS, Joe and Beta. They are all on distinct and
non-connected networks.
They were all sending email to McQ, a Postfix mail server on port 587
(Fedora 42).
The other day, NAS just stopped sending email.
The IP isn’t blocked (at either the Pi or McQ). I can traceroute to
McQ. I tried nc, telnet and open_ssl to attempt connecting on port
587, and they all failed from NAS to McQ. However, they did work on
Joe and Beta to McQ.
The credentials didn’t change. The conf file, except for the name of
the server are identical.
Any ideas?
Thank you.
Regards,
Wayne
Hello,
Have you noticed error messages your logs? There usually are when emails
fail to send. smtpctl can show the current queue and set verbose logging
and tracing of subsystems if it helps.
If you say that other software can’t connect to the port either then it
seems like a network issue: you can try running tcpdump or wireshark on
both machines when attempting to connect to see if packets are being
dropped at some point.
You may also want to double-check your firewall rules, especially if
running something like fail2ban.
Hope it helps.
