Domain Logon Attempt Does Not Work with M-Node Clients Using WINS Proxy Agent (233517)

CAUSE

This behavior occurs when you have a WINS proxy agent on your computer's local subnet, but all of your domain controllers are on remote subnets.

If an m-node client resolves a NetBIOS group name using broadcast in Windows NT 4.0 Service Pack 5 or earlier, the client assumes that the related computers can also be reached using broadcast. If there is a WINS proxy agent on the local subnet, the WINS proxy agent may respond to name query broadcasts and resolve them to computers on remote subnets.

For additional information about WINS proxy agent functionality, please see the following article in the Microsoft Knowledge Base:

121004 WINS Proxy Agent Functionality

RESOLUTION

Windows NT Server or Workstation 4.0

To resolve this problem, obtain the latest service pack for Windows NT 4.0 or the individual software update. For information on obtaining the latest service pack, please go to:

http://www.microsoft.com/windows/servicepacks/ -or-
152734 how to obtain the latest windows nt 4.0 service pack

For information on obtaining the individual software update, contact Microsoft Product Support Services. For a complete list of Microsoft Product Support Services phone numbers and information on support costs, please go to the following address on the World Wide Web:

http://support.microsoft.com/directory/overview.asp

Windows NT Server 4.0, Terminal Server Edition

To resolve this problem, obtain the latest service pack for Windows NT Server 4.0, Terminal Server Edition. For additional information, click the following article number to view the article in the Microsoft Knowledge Base:

152734 How to Obtain the Latest Windows NT 4.0 Service Pack

MORE INFORMATION

The following information assumes that the client computer is a member of the domain named DOMAIN.

Before you can log on, the client must resolve the DOMAIN[1C] NetBIOS group name to locate a domain controller to act as a logon server. An m-node client computer uses two methods to resolve the group name. It first attempts to resolve the name by broadcast. If broadcasting does not resolve the name, it attempts to resolve the name by directly querying its WINS server.

If a WINS proxy agent exists on the local subnet, it is likely that the WINS proxy agent will respond to the initial broadcast name query for DOMAIN[1C] before the workstation attempts to query its WINS server. In this situation, the client notes that the name is resolved using broadcast, and assumes that the related computers can also be reached using broadcast. It never uses any IP addresses returned in the name query response from the WINS proxy agent.

When the client moves on to send SAM LOGON requests, it sends the requests only as broadcasts, and does not send them directly to any domain controller. If there are no domain controllers on the local subnet, the client does not locate a logon server and logon attempts are unsuccessful.

Network Monitor Capture of the Behavior

In frames 1 and 2 in the example below, the client attempts to resolve DOMAIN[1C] using broadcast, with the WINS proxy agent responding.

In frames 3-5, the client attempts to contact a logon server by using broadcast. Note that there is no attempt to contact the logon server directly, using the address returned in frame 2 by the WINS proxy agent.

After a timeout occurs, the user is logged on with cached credentials and the client registers the logged-on user's name (first using broadcast in frames 6-9, and then using the WINS server in frames 10 and 11).

Frame Time   Source  Destination   Protocol  Description

  1   0.000  Client  *BCAST        NBT       NS: Query req. for DOMAIN<1C>
  2   0.000  Proxy   Client        NBT       NS: Query resp. for DOMAIN<1C>, Success
  3   0.001  Client  *BCAST        NETLOGON  SAM LOGON request from client
  4   5.002  Client  *BCAST        NETLOGON  SAM LOGON request from client
  5   5.008  Client  *BCAST        NETLOGON  SAM LOGON request from client
  6  14.975  Client  *BCAST        NBT       NS: Registration req. for USER<03>
  7   0.749  Client  *BCAST        NBT       NS: Registration req. for USER<03>
  8   0.751  Client  *BCAST        NBT       NS: Registration req. for USER<03>
  9   0.752  Client  *BCAST        NBT       NS: Registration req. for USER<03>
  10  0.000  Client  WINS          NBT       NS: Registration req. for USER<03>
  11  0.009  WINS    Client        NBT       NS: Registration resp. for USER<03>, Success

When the hotfix is applied, the client sends a directed SAM LOGON request immediately after the first broadcast SAM LOGON request in frame 3, and the logon attempt is successful.