When you change the hostname in Ubuntu you usually have to change it in /etc/hostname and do "hostname
" on the command line as well. Also, log out and log back in.. It should change it in the prompt. You'll also have to make sure the /etc/hosts file is correct then as well.
The hostname inconsistencies is what I've been trying to get at... it was being listed as zimbra.pdadmin.com. Also, in the last zone file you posted there's no A record for mail2, only for mail. There's an MX record that points the domain to mail2 but no A record saying what mail2 is.