I saw a flow chart once upon a time that showed how mail flows through the Zimbra system, but I can't find it.
I see that I made 5 VMs on an old virtual server for Zimbra, but I can't figure out how I was dividing up into 5 systems. I'm hoping that chart refreshes my memory.
Looking at the multiserver installation guide now, I see 4: Master LDAP, replica LDAP, MTA, and Mailserver. I'm not sure if I had another MTA, mailserver, or some other component sat on that other VM.