Hosting multiple domains on Mac OS X Server

There are two ways to set up multiple email domains on OS X Server: you can add aliases (which share the same account names, e.g. [email protected] and [email protected] go to the same mailbox) or virtual domains (which can have different accounts).

Adding alias domains is easy: in Server Admin -> Mail service -> Settings -> Advanced -> Hosting, add the additional domains to the Local Host Aliases list.

Virtual domains are a little more complicated. Add the virtual domain names in Server Admin -> Mail service -> Settings -> Advanced -> Hosting -> Locally Hosted Virtual Domains (and check the enable box). Then, to create users for this domain, create them as usual in Workgroup Manager, and add their full virtual alias as secondary short names (e.g. you might create a user with the primary short name "alice-otherexample", and a second short name of "[email protected]"). Alice can then receive mail using an account name of either "alice-otherexample" or "[email protected]". Note that users for the server's primary domain name (or its aliases) don't have to bother with these funny names, they just access their mailboxes by their usual shortname.

In either case, make sure you also set up the DNS properly; you need MX records for all domains you receive mail from, pointing to your server's hostname.