I just installed Zimbra yesterday, and it looks pretty good. I really like the search feature. I am currently running a Courier mail server with an OpenLDAP backend and squirrelmail, and I'm just looking at what else is out there.

I have a few questions though..

Do the Zimbra users live in LDAP?
I can only see the admin user zimbra.
How can I use the Purchase Order Identifier?
In cn=po,cn=object,cn=config,cn=zimbra, I can see it, do I just have to match it against a regular expression?

I'd like to set up a filter so that Zimbra will authenticate against an external LDAP server, but I'm not sure where to start.

I am using the 3.0.0_M2_746 FC4 release.