Not able to start postfix.service after re-installing

[eclay]

I was trying to setup postfix/dovecot and was having issues getting both to work. My thought was to uninstall and then reinstall fresh and give it another try. After using 'apt -y purge postfix' Then trying to reinstall using 'apt install postfix' The service fails to start. Using 'systemctl start postfix' shows the following.

systemctl status postfix
● postfix.service - Postfix Mail Transport Agent
Loaded: loaded (/usr/lib/systemd/system/postfix.service; enabled; preset: enabled)
Active: active (exited) since Tue 2024-05-07 16:40:48 MDT; 10min ago
Docs: manostfix(1)
Process: 7151 ExecStart=/bin/true (code=exited, status=0/SUCCESS)
Main PID: 7151 (code=exited, status=0/SUCCESS)
CPU: 1ms


May 07 16:40:48 server.domain.com systemd[1]: Starting postfix.service - Postfix Mail Transport Agent...
May 07 16:40:48 server.domain.com systemd[1]: Finished postfix.service - Postfix Mail Transport Agent.

Not getting anything useful when running 'journalctl -xeu postfix.service'. Just says that a start job has finished.

I am able to start it using the postfix commmand.
postfix -c /etc/postfix startpostfix/postfix-script: starting the Postfix mail system

ps aux|grep postfix
root 7654 0.0 0.0 42848 4764 ? Ss 16:54 0:00 /usr/lib/postfix/sbin/master -w
postfix 7655 0.0 0.0 43300 7936 ? S 16:54 0:00 pickup -l -t unix -u -c
postfix 7656 0.0 0.0 43340 7936 ? S 16:54 0:00 qmgr -l -t unix -u

I can now connect to port 25.
telnet localhost 25
Trying 127.0.0.1...
Connected to localhost.
Escape character is '^]'.

Anyone have any ideas what might be preventing this from starting? I believe that postfix runs in a chroot. So I also try disabling that in /etc/postfix/master.cf.

[eclay]

I ran a similar test on ubuntu 22.04 by installing postfix and seeing that it was running. I then did a 'apt purge postfix' followed by removing /etc/postfix and /var/spool/mail. I then reinstalled postfix and the service shows running. This seems to be an issue with 24.04 only.

root@ubuntu3:~# ps aux|grep postfix
root 1597 0.0 0.2 41232 4804 ? Ss 16:46 0:00 /usr/lib/postfix/sbin/master -w
postfix 1599 0.0 0.3 41560 6988 ? S 16:46 0:00 pickup -l -t unix -u -c
postfix 1600 0.0 0.3 41604 6996 ? S 16:46 0:00 qmgr -l -t unix -u
root 1756 0.0 0.1 6480 2236 pts/1 S+ 16:48 0:00 grep --color=auto postfix
root@ubuntu3:~# systemctl status postfix
● postfix.service - Postfix Mail Transport Agent
Loaded: loaded (/lib/systemd/system/postfix.service; enabled; vendor preset: enabled)
Active: active (exited) since Wed 2024-05-08 16:46:39 UTC; 1min 58s ago
Docs: manostfix(1)
Process: 1598 ExecStart=/bin/true (code=exited, status=0/SUCCESS)
Main PID: 1598 (code=exited, status=0/SUCCESS)
CPU: 1ms


May 08 16:46:39 ubuntu3 systemd[1]: Starting Postfix Mail Transport Agent...
May 08 16:46:39 ubuntu3 systemd[1]: Finished Postfix Mail Transport Agent.

[eclay]

Found the solution. I compared the /var/spool/postfix on my system with another ubuntu 24.04 system that postfix was installed and running on. I found that serveral directories/files where missing. I noticed that on my test system, I could uninstall postfix and reinstall it. I also noticed that ssl-cert and libnsl2 packages where installing/uninstalling on the working system. It looks like my server wasn't uninstalling ssl-cert package when I uninstalled postfix. So when I delted the directories and then tried to reinstall things where missing.

solution:
apt purge postfix ssl-cert libnsl2
apt install postfix