Thanks to the reasonably good descriptions in this thread, I think I understand the independent concepts of a "Public Service Host Name" and Virtual Hosts. But what I'm not sure of is how they work together and what the usual practices regarding them are.

Let's say I have a single Zimbra server called I'd like to set up mail service for, whose MX record is going to point to the A record "" which holds the address of the Zimbra server. Do I need to set the PSHN as well as create a virtual host? What would be the implications of setting only one? What if they differ, for example an MX of '' but a webmail URL of ''.

Any insight into best practices or caveats would be great... thanks!