I am trying to troubleshoot after an update using apt-get update/upgrade I did a few days ago on Debian 9 (now 10). PostFix does not seem to work anymore. I tried many things: rebooting, restarting postfix, upgrading debian from 9 to 10. But it is still not working as before.
I confirmed that the master.cf and main.cf were not changed by the installer. Is there a troubleshooting guide somewhere? Here is some info I got: # service postfix status ? postfix.service - Postfix Mail Transport Agent Loaded: loaded (/lib/systemd/system/postfix.service; disabled; vendor preset: enabled) Active: active (exited) since Fri 2020-10-09 05:26:54 PDT; 6min ago Process: 3059 ExecStart=/bin/true (code=exited, status=0/SUCCESS) Main PID: 3059 (code=exited, status=0/SUCCESS) Oct 09 05:26:54 ...: Starting Postfix Mail Transport Agent... Oct 09 05:26:54 ...: Started Postfix Mail Transport Agent. # postfix -v check postfix: name_mask: all postfix: inet_addr_local: configured 5 IPv4 addresses postfix: inet_addr_local: configured 2 IPv6 addresses postfix: Postfix is running with backwards-compatible default settings postfix: See http://www.postfix.org/COMPATIBILITY_README.html for details postfix: To disable backwards compatibility use "postconf compatibility_level=2" and "postfix reload" postfix/postfix-script: warning: symlink leaves directory: /etc/postfix/./makedefs.out postfix/postfix-script: warning: /var/spool/postfix/etc/ssl/certs/ca-certificates.crt and /etc/ssl/certs/ca-certificates.crt differ postfix/postfix-script: warning: /var/spool/postfix/lib/i386-linux-gnu/libnss_systemd.so.2 and /lib/i386-linux-gnu/libnss_systemd.so.2 differ I looked at the log and saw similar warnings as above: Oct 9 05:35:00 ...: name_mask: all Oct 9 05:35:00 ...: inet_addr_local: configured 5 IPv4 addresses Oct 9 05:35:00 ...: inet_addr_local: configured 2 IPv6 addresses Oct 9 05:35:00 ...: Postfix is running with backwards-compatible default settings Oct 9 05:35:00 ...: See http://www.postfix.org/COMPATIBILITY_README.html for details Oct 9 05:35:00 ...: To disable backwards compatibility use "postconf compatibility_level=2" and "postfix reload" Oct 9 05:35:04 ...: warning: symlink leaves directory: /etc/postfix/./makedefs.out Oct 9 05:35:04 ...: warning: /var/spool/postfix/etc/ssl/certs/ca-certificates.crt and /etc/ssl/certs/ca-certificates.crt differ Oct 9 05:35:05 ...: warning: /var/spool/postfix/lib/i386-linux-gnu/libnss_systemd.so.2 and /lib/i386-linux-gnu/libnss_systemd.so.2 differ Oct 9 05:35:05 ...: postfix/postqueue[...]: warning: Mail system is down -- accessing queue directly I looked at the postfix compatibility web page but I am not sure what options make it go into compatibility mode. Also the above are warnings so I am guessing this would not prevent postfix from running. Or maybe warnings are considered unacceptable? I also tried this: apt-get install --reinstall postfix Do I really need to do these? postconf compatibility_level=2 postfix reload