Short story: when upgrading a production system, always check the release notes of the new version.
After the first upgrade of the server following the release of the new Debian stable, I was no more able to send e-mail from my home pc, but I am still able to send from the server itself, which is running Debian testing, so in the following days of the Debian release, testing got a lot of upgrade as usual.
This upgrade also boost postfix to the 2.1.0 release.
Sending mail from my home pc, then result in the error:
May 11 09:28:22 localhost postfix/smtpd: connect from unknown[22.214.171.124]
May 11 09:28:24 localhost postfix/smtpd: NOQUEUE: reject: RCPT from unknown[126.96.36.199]: 554 5.7.1
<gianlum@xxxxxxx>: Relay access denied; from=<firstname.lastname@example.org> to=<gianlum@xxxxxxxx> proto=ESMTP helo=<galactica>
May 11 09:28:24 localhost postfix/smtpd: lost connection after RCPT from unknown[188.8.131.52]
May 11 09:28:24 localhost postfix/smtpd: disconnect from unknown[184.108.40.206]
It turn out that from this release on, to be able to have a relay (from home I send mail using my server and not the provider's one), you should put the client restriction in the directive
instead of the old
as always in the main.cf file
I discovered this the hard way, since I was in a hurry to send a mail, and before I can find this change, I tried a gazillion other solutions and also checked for every blacklists in the case the server and/or my provider nerwork were blocked.
So, lessons learned:
- Always read the release notes (or at least, check them for the important software)
- Do not try massive upgrade past 10.00 pm or you will end to lose sleep and do not solve anything anyway, at least until the next morning
- If you need to send a very urgent email, send it before trying a massive upgrade :-D