Since a few hours, altough I did nothing special on my Zimbra server, a huge mass of mails have been sent from it.
I did some checks, and it seems my server is not an open relay.
I also locked every accounts, but the mails go on being sent from my server.

What is strange is that they are sent by service@mydomain.com (from filed), but no "service" account seems to exist.

PLease help me, I really don't know what to do !