I've been running a zimbra OS 5.0.16 opensuse 10.2 install for sometime now, with no apparent issues.
However, during the commissioning phase i had the domain different.
i also had the hostname different mx1.zimbra-[mydomain].com
since then, i have performed the necessary changes to make it proper..
domain = [mydomain].com
hostname = [mx1.[mydomain].com
both using the documented commands.
and more recently, ammended errors in the zmlocalconfig.
i've been perusing the logs and have found an issue though...
it seems the system is still sending occasional alerts to the old domain.