The plot is thickening here. I'm pretty confident my problem is NOT related to a catch all account.
I originally had this server set up as "secondary" for a split domain situation (a qmail server was primary). Eventually I moved all the accounts over to my zimbra server, and changed the mx record. However, I never changed my zimbraMailTransport value back.
Currently it's set to: smtp

ldserver.domain.com
So, I'm relaying all outbound off my old server (not good obviously).
I have no idea what the true value should be...unless it should just be:
smtp:newserver.domain.com where newserver is the name of the machine that I'm hosting zimbra on.
Thoughts?