SonicWALL 300 manual Message Management section, configure, NetBIOS domain, Names

NetBIOS domain	In a Microsoft Windows environment, users are grouped
names:	under NT Domains and they are authenticated against the
	one particular NT Domain they are grouped in.
	Whatever list is specified here is offered as a pull-down menu
	to users on the Login page. The intent is to provide users who
	are used to logging in to their Microsoft Windows computers
	the identical interface they are normally presented with. The
	effect is that the NT Domain string is prepended to their login
	name when doing authentication.
	Example:
	The administrator adds both sales and engr to the Domain
	List. Then when a user named JohnS with email address
	JohnS@example.com logs in, he will be presented with a
	pull down menu. If he chooses "sales", and types "JohnS" as
	his login name, the real login name that is passed to Active
	Directory for authentication is "sales\johns".

3. In the Message Management section, configure:

Action for messages identified as junk:

Select to quarantine all junk mail or deliver all mail to users.

SonicWALL Email Security Getting Started Guide Page 23