Currently, /var/log/zimbra.log has the date, time, sender, and recipient for each message processed by the mail server. In order for us to comply with some new rules handed down to us, we would like to log the subject line of each email in this log as well.

I tried adding the following line to /opt/zimbra/conf/postfix_header_checks.in:
Code:
/^subject:/      WARN
and restarted the MTA (zmmtactl restart). I have not seen a change in the main log file, though. I'm sure that I am missing something simple, but I can't figure it out. Any ideas?