I am trying to learn more about Zimbra and how exactly to monitor whats going on (and coming out of) my Zimbra server. I understand where the logs are, and what they represent. I just was wondering if there was some better way to compile the data in the logs to something more readable (like amount of mail sent out by a single user in a day). I have seen the "Server Statistics" in the admin console, it provides only generalized output (useless for my purposes). Any suggestions?

Also, today I came accost an "Undelivered Mail Returned to Sender" message that one of my employees sent to a client, heres the returned e-mail after "the mail system's" response:

<llizotte@client.com>: host mx1.emailsrvr.com[] said: 550
5.1.1 <llizotte@client.com>: Recipient address rejected: User
unknown in relay recipient table (in reply to RCPT TO command)

"mx1.emailsrvr.com" is not my email server, does this mean that the problem lies in our server or elsewere? My employee was able to send this guy e-mails just yesterday. I checked the blacklists and it seems my server and theirs is in the clear. How do I remedy this problem?