+++ This bug was initially created as a clone of Bug #105045 +++

Description of problem:

When using Domain and ADS security, the "Preferences->Server
Settings->Security->Authentication Server" field must have a non-NULL value or
the tool doesn't let the user commit the settings, and brings up a dialog with
the text: "You must specify a password server when using 'ads', 'domain' or
'server' authentication."

This isn't strictly true, and is confusing to samba neophytes or infrequent
users (like myself). smb.conf permits a value of "*" to be entered to permit the
password server to be auto-located. The Windows clients that I've seen at the
companies I've worked at are configured to use auto-location (I don't even know
if it can be overridden). Presumably a nice benefit of this approach is that it
gives admins an option to change the server IP without needing to maintain the
clients.

At a minimum, the text of the dialog should be modified to indicate that "*" is
a permissible value for auto-location, since many users may not be familiar with
this detail of smb.conf's format.

A better solution (I think) would instead let the user select either
auto-location or manual setting with a ui control, and only permit the server
name to be entered if manual were chosen.