Very weird problem. I have installed Zimbra at a clients site (25 users). They are accessing it via web, Eudora and Thunderbird (Mac). Occasionally, it will lock up and no one inside their network can access the server. After I bump the service (zmcontrol stop ; zmcontrol start), all is well. It appears to be doing this one or two times a day. I have no problems ssh'ing into the machine, and at least one time I was able to check mail from the outside, but no one on the inside could do so until I' had bumped the service.
They had a very active web server on the same paired T1's which was saturating the network, but we moved that machine and network traffic is down. The main traffic now is e-mail, all handled by zimbra.
Any suggestions? I see nothing horrible in /var/log/zimbra.log. Any suggestions on where to look next time this happens, or how to troubleshoot this. The client is willing to be without e-mail for a short time if I can successfully troubleshoot the problem.