after no mail was sent out today by our UCS-server, i found the root cause for this within the postfix configuration file (main.cf). At least 2 lines were changed/deleted (e.g.):
smtp_sasl_password_maps = hash:/etc/postfix/sasl_passwd
was replaced with:
smtp_sasl_password_maps = hash:/etc/postfix/smtp_auth
smtp_use_tls = yes was removed completley.
After fixing this two lines and restarting the postfix-service, sending mail is working again.
Furthermore I can see now the following warning in the mail.log file:
Postfix is running with backwards-compatible default settings See http://www.postfix.org/COMPATIBILITY_README.html for details To disable backwards compatibility use "postconf compatibility_level=2" and "postfix reload"
Im wondering now if this needs to be applied and what else was changend or needs to be taken into account after the update to 4.3.1?
Any hint would be much appreciated, thx.