Zimbra 5.0.9 on OpenSuSE 10.2.
Server has been running 6 months.
No new software added or updates to OS.
No configuration changes.

Overnight MTA stopped responding. IMAP worked, Web Access worked, but unable to send or receive email. Where can I look to find clues as to what went wrong. There are a lot of logs in /opt/zimbra/log. I went through a couple of them but not seeing much related to the SMTP MTA itself.