WINS Does Not Replicate <1c> Names Properly

- Microsoft Windows NT Server versions 3.5 and 3.51

SYMPTOMS

Among Windows Internet Name Service (WINS) servers, the [1C] group name is not replicating properly, resulting in certain WINS databases that contain only a partial list of domain controllers in the [1C] group.

CAUSE

The [1C] record is not replicated because the [1C] version ID was not updated to indicate that it had changed.

Description of Problem

When a DC registers with a WINS server, the DC will register its IP address in the <domain>[1C] group, (along with any other servers already listed,) and the WINS server will update the 'version ID' of that [1C] record. That record will then get propagated from the WINS server, to a partner-WINS server.

If the partner-WINS already has a previous replica (copy) of the [1C] record, it will update its own database to include the new IP addresses in that record, but it will not update its version ID of that [1C] record. (The original WINS and the partner-WINS will maintain different version IDs of the records that they pass to each other.)

At this point the partner-WINS has an updated [1C] record, however it will not push that record to a third partner-WINS because the version ID was not updated.

For example:

Assume a network with at least 3 WINS servers WINS_X, WINS_Y, and WINS_Z; where WINS_X is the primary WINS server that all DCs register with; WINS_Y and WINS_Z are sequential partners; thus, during propagation the flow of the [1C] group is as follows:

   (WINS_X)  -->  (WINS_Y)  -->  (WINS_Z) ....

The result of this is that the domain controllers in the list at WINS_Z may get overloaded with network requests; and DC redundancy is reduced.

WORKAROUND

To work around this problem, you have three options.

• This option works best if you have all DCs registering at one WINS:

  1. Use WINSCL.EXE (from the Windows NT Resource Kit) to delete the [1C]

        entry on all WINS databases that merely contain a replica of the
        record (that is, no DCs are registering to those WINS servers). Also
        delete any static [1C] record from any WINS (because the 'migrate
        on' feature will not resolve the problem.)
  

  2. From your WINS server(s) that accepts DC registrations, do something

        to cause an update to the [1C] record, such as rebooting a DC, or
        typing IPCONFIG /RENEW if you are using DHCP.
  

  3. Force propagation to all partner WINS servers. Since owner [1C]

        records are updated, and the partners do not have any replica copy
        at all, it should get completely replicated because it is a new
        record (and high version ID) at every partner.
  

  -or-

• Set up your WINS push/pull configuration in a star pattern, such that there is a central WINS where all your DCs register, and the partner WINS servers only replicate with the central server. In this configuration the problem should not occur at all.

  -or-

• Although Microsoft generally does not recommend using Static entries for computers that are WINS aware, you can overcome this problem by creating a static record for the [1C] domain name. This will disable the functionality of controllers dynamically registering their address in the [1C] group, however it will allow you to manually add controllers to the [1C] record on any partner WINS database, and thus have control of the list.

  NOTE: If you have a Windows NT 3.1 DC in your domain, this static method will be required because Windows NT 3.1 is not WINS aware.

RESOLUTION

This problem has been corrected in the latest Service Pack for Windows NT version 3.51.

STATUS

Microsoft has confirmed this to be a problem in Windows NT version 3.51. This problem was corrected in the latest Windows NT 3.51 U.S. Service Pack. For information on obtaining the Service Pack, query on the following word in the Microsoft Knowledge Base (without the spaces):

   S E R V P A C K

MORE INFORMATION

The [1C] (that is, [1Ch] or [0x1Ch]) is a special group name registered for use by the domain controllers (DCs) within the domain, and can contain up to 25 IP addresses.

In a large network with more than 25 DCs, new registrations will overwrite the oldest ones. This means that the primary DC (PDC) will remain in the [1C] list unless it gets overwritten, too. However, when a client does a query for the [1C] list, the PDC address will still be returned because the PDC registers the <domain>[1B] name, and that address will always be returned with the [1C] list.

The [1C] domain name is used for the following functions:

• Domain logon process through WINS (when Windows for Workgroups, Windows95, and Windows NT clients log on):

  1. A client will send a name query to the WINS server for the

        <domain name>[1C].
  

  2. The WINS server will return the list of IP addresses (DCs) in the

        [1C] group.
  

  3. The client will send a directed datagram to each DC in an attempt to

        logon to the domain.
  

  4. The DCs will start responding to the logon request.

  5. The client will continue the logon process with the first DC that

        responds; the client will ignore the other responses.
  

• Secure Channel establishment:

      -  Interdomain: When Windows NT workstations and servers are started,
         they will use the [1C] list of addresses to find a DC and establish
         a secure channel for their domain machine account.
  

      -  Trusted domains: When a DC comes up, it will set up a secure
         channel with a DC from the <remote domain>[1C] list. This channel
         will be used for pass-through authentication.