7.3 Special Handling Required for 0x1B Names

7.3 Special Handling Required for 0x1B Names

A Domain Master Browser (a special kind of Master Browser, which is described later on in the book) will register unique names with a suffix of 0x1B . These names get special treatment in WINS. Whenever a 0x1B name is registed in WINS, the WINS server will look for a matching 0x1C group name and modify the entry.

As you may recall from our diatribe in the Datagram section, 0x1C group names are "Internet Group" or "Special Group" names, and WINS will keep track of 25 IP addresses per 0x1C group name. The weird thing is that WINS also sorts this IP list so that the IP address associated with the 0x1B name is at the top of the list.

Why?

Well, see, the 0x1C names represent the set of Domain Controllers for a given NT Domain. Only the Primary Domain Controller is allowed to run the Domain Master Browser service and register the 0x1B name. So, by sorting the IP list, WINS ensures that the IP address of the Primary Domain Controller is always the first IP address in the 0x1C list of Domain Controllers.