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 zimbrasrv.mycompany.com. I'd like to set up mail service for domain.com, whose MX record is going to point to the A record "mail.domain.com" 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 'mail.domain.com' but a webmail URL of 'webmail.domain.com'.

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