Logon using full email address only

[gra]

Can users be forced to logon using their full email address as opposed to just their username?

If so, how would I go about disabling / enabling this feature?

[ewilen]

It sounds like you want the reverse of the Virtual Host feature.

I suppose you could accomplish this by creating a domain within Zimbra that is different from the server's DNS name, and putting all the users into that domain. Then as long as you don't configure a virtual host for that domain, users will have to use their full email address.