User activation link points to localhost

After much trial and error we now have Omeka 2.3.1 running on OS X 10.10.5 Yosemite, with the Server App installed.

When a new user is created he/she gets the confirmation email (which is being sent correctly) but the confirmation link lists 'localhost' instead of the server address, which (obviously) doesn't work for activation The link looks like this: http://localhost/dm/admin/users/activate?u=yyyyyyyy (numbers removed)

Is it possible to change how this link gets generated? Any advice on how/where this can be configured would be most helpful, since we must have activation for the project.

Here's a rare occasion where experimenting worked. It turns out that if one is logged in through a browser using localhost on the server then the activate email sent to a newly created user lists "localhost" as the return link.

Switch to a different computer that uses the site's full name
and the email sent to a newly created user generates the correct activation link.

I have no idea if this is how it supposed to work, but at least the solution is clear: always administer with remote logins.