Debian upgrade from bullseye to bookworm with a virtualmin container

SYSTEM INFORMATION
debian 12 REQUIRED
Webmin version 2.520 REQUIRED
7.50.0 GPL REQUIRED
apache2 REQUIRED

I did an upgrade yesterday by simply changing the /etc/apt/sources.list from bullseye to bookworm.

 apt update
 apt upgrade --without-new-pkgs
 apt full-upgrade

Everything for the package installations went well. I expected some issues with dovecot mailboxes or anything I might have custom changed. But the major issue I got was postfix and and an error I do not believe I’ve seen before.

SASL authentication failure: cannot connect to saslauthd server: No such file or directory

In the end, my understanding was that Postfix is chrooted and was not talking to saslauthd. I had to look for online help and use chatGPT

I think there is a lot missing from the notes I took, because I had another container to update and followed these instructions could not get it working and had to revert the container.
But if anyone can explain more about what is going on or if it was just by luck I fixed it please sahre.

saslauthd was running but I was getting the no such file or directory.

executing this command worked

/usr/sbin/saslauthd -a pam -c -m /var/spool/postfix/var/run/saslauthd -n 5

chatGPT
Postfix chroot issue:
On many systems, especially with Virtualmin/Webmin, Postfix runs the SMTP daemon (smtpd) inside a chroot (/var/spool/postfix). Inside the chroot, /var/run from the host isn’t visible. So when Postfix tried to contact saslauthd at /var/run/saslauthd/mux, it couldn’t find it, producing:

cannot connect to saslauthd server: No such file or directory

Why your command fixed it:
By starting saslauthd with:

bash
Copy code
-m /var/spool/postfix/var/run/saslauthd
you told saslauthd to create its socket inside the Postfix chroot. Now smtpd can see and communicate with the socket directly, bypassing all the previous “file not found” issues.