WINS Allows Duplicate Name Registrations Across Slow Link

• Microsoft Windows NT Workstation versions 3.51 and 4.0
• Microsoft Windows NT Server versions 3.51 and 4.0

SYMPTOMS

When a Windows Internet Name Service (WINS) server is operating across a slow wide area network (WAN) link, it allows workstations and servers to register duplicate names, causing connectivity problems on your network.

CAUSE

The WINS Server name challenge may time-out on a slow WAN link, which may allow a computer to register a duplicate name on the network.

RESOLUTION

Obtain the fix mentioned below, then use the following steps to configure the number of retries and the time interval for the initial retry attempt that WINS uses for name challenges and responses:

WARNING: Using Registry Editor incorrectly can cause serious, system-wide problems that may require you to reinstall Windows NT to correct them. Microsoft cannot guarantee that any problems resulting from the use of Registry Editor can be solved. Use this tool at your own risk.

1. Run Registry Editor (Regedt32.exe).

2. Go to the following key in the registry:

         HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\WINS\Parameters
   

3. Click Add Value on the Edit menu and type the following information to create two new registry values:

         Value: ChlMaxNoOfRetries
         Data Type: REG_DWORD
         Default = 3
         Description: This parameter determines the number of retries WINS
                      Server will do for the name challenge query.
   
         Value: InitChlRetryInterval
         Data Type: REG_DWORD
         Default = 500(milliseconds)
         Default: This parameter sets the initial retry interval for name
                  challenge query. The interval is doubled for each subsequent
                  retries. For example, if ChlmaxNoOfRetries is set to 4 and
                  InitChlRetryInterval is set to 1000, the first retry will be
                  1000ms later and the following retries will be at 2000ms,
                  4000ms, 8000ms, and so on.
   
   

4. Exit Registry Editor.

5. Stop the WINS Server by typing the following at a command prompt, then pressing ENTER:

         net stop wins
   

6. Restart the WINS server by typing the following at a command prompt, then pressing ENTER:

         net start wins
   

STATUS

Microsoft has confirmed this to be a problem in Windows NT versions 3.51 and 4.0. A supported fix is now available, but has not been fully regression-tested and should be applied only to systems experiencing this specific problem. Unless you are severely impacted by this specific problem, Microsoft recommends that you wait for the next Service Pack that contains this fix. Contact Microsoft Technical Support for more information.

MORE INFORMATION

When a WINS client sends a name registration request to its WINS Server for a name that already exists, the WINS server sends a challenge request to the computer that registered earliest. If there is no response to the challenge, the WINS server will try two more times at 500-microsecond intervals. This was previously a hard-coded value and could not be configured.

If the computer is operating across a slow link, it is possible that the response will take too long, causing a time-out on the WINS server. The new computer will then be successfully registered on the WINS server, which will cause two computers to use the same name on the network.