Please change the DNS lookup = defaultdomain process, and use defaultdomain as the default domain.

[josh at endries.org]

Okay, defaultdomain is set to mail.blah.com again, as it should be.

Logging in as admin at mail.blah.com now doesn't work, reports the user  
name as 'admin', correctly, but doesn't work.

Logging in as admin doesn't work, reports the user name as  
user at blah.com and the password for that user is (now) different.

With the defaultdomain set to something else, like something.fake,  
logging in as admin at mail.blah.com works but then of course is not a  
global admin.

Changing defaultdomain to blah.com, which kinda makes sense but  
shouldn't be forced...using admin tries login as admin and doesn't  
work (doesn't append blah.com?). Logging in as admin at blah.com also  
tries login as admin and doesn't work.

e.g. by "tries login as..." I mean "admin" in:

Jul  1 11:02:38 mail imaps[19476]: badlogin: mail.blah.com [x.x.x.x]  
plaintext admin SASL(-13): authentication failure: checkpass failed

This was from logging in with

c login "admin at blah.com" "password"

Still working on it...

Josh