I'm seeing the messages below in /opt/zimbra/log/access_log.2013-07-24
I have grep-ed for the lines containing "unknown". The only changes from the actual log are the domain and user names.
How can httpd not know the source IP of some requests?
Edit: Forgot to mention the Zimbra version. Here it is:
Zimbra 8.0.2_GA_5569 (build 20121210115059)