[SOLVED] Postfix in LXC debian templates

[ulvida]

AFAIK, exim is the debian default MTA. However, proxmox LXC templates for debian come with postfix installed instead of exim. And, most of all, the /etc/mailname is not created and populated at configuration.

This breaks the installation or configuration of some packages (like sympa) which rely on an appropriate MTA configuration, with /etc/mailname file.

Once the problem undestood, it's not difficult to script a workaround, but it was not easy to identify, and it's not very clean and portable.

So I was the wondering how Proxmox LXC templates are built. I found this thread and read about DAB, but the links in this post are no longer availables and, as far as I can undestand, these DAB configuration files for Debian 10 templates don't include any customization, so I can't understand why and how debian templates come with postfix half installed and not with exim.

Thanks in advance for your lights.

 

[dietmar]

Templates are created with dab, and dab uses postfix as default MTA. But the file /etc/mailname is a specific configuration, i.e. we cannot configure that in the template.

 

[Stoiko Ivanov]

Postfix works fine without '/etc/mailname' present - it sets '$myorigin' to the fqdn of the host (see `man 5 postconf` and [1]).
The configuration of the package in the debian templates is defaulting to a internet connected site - which is the only option, without any other information pointers (like a smarthost) - just like we cannot sensibly set '/etc/mailname' as @dietmar pointed out.

The issue with sympa is that the postinst script had a bug - [0] (using 'hostname -fqdn' instead of 'hostname --fqdn`), which has been fixed in the package version 6.2.40~dfsg-3 (buster still has 6.2.40~dfsg-1).

I hope this explains it.


[0] https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=935882
[1] https://wiki.debian.org/EtcMailName

 

[ulvida]

Waw! Thanks for all this insight! If fully explains my doubts. I'll wait to learn more about DAB before asking more questions. Thanks a lot.

 

[Stoiko Ivanov]

Glad we managed to point out a few things - feel free to ask if you run into other questions!
(It helped me to verify that '/etc/mailname' does not need to be set