One thing you can try is a modification to the nsswitch.conf file. Check this
post from dwill and see what the format of the 'hosts' line is in that file. See if it looks like this:
Code:
hosts: files mdns4_minimal [NOTFOUND=return] dns mdns4
if it does then modify it to the following:
Code:
hosts: files dns mdns
and see if that helps. You'll also be doing a test for dwill by doing that.
If that isn't the answer or doesn't work the please do the following on the Zimbra server:
Code:
host `hostname` <-- backticks not single quotes
cat /etc/hosts
cat /etc/resolv.conf
dig yourdomain.com mx
dig yourdomain.com any
and post the output here.