NetBT Domain 0x1C Name Fails to Add All #DOM IP Addresses

• Microsoft Windows NT Server version 3.5

SYMPTOMS

When Netlogon sends discovery mailslots to find a domain controller in a trusted domain, it fails to send directed mailslots to all the domain controllers defined in the LMHOSTS file with the trusted domain name.

You can see the results in the following sample LMHOSTS file and trace. Even though TTOWN5 is defined as an AMERICA Domain Controller, it is never sent a directed mailslot for Netlogon, therefore it may never be used for authentication by a trusting domain.

LMHOSTS file contents:

   144.249.168.234 CIMCON       #DOM:AMERICA        #PRE
   144.249.168.104 TTOWN1       #DOM:AMERICA        #PRE
   144.249.13.207  TTOWN2       #DOM:AMERICA        #PRE
   144.249.168.105 TTOWN3       #DOM:AMERICA        #PRE
   144.249.169.16  TTOWN4       #DOM:AMERICA        #PRE
   144.249.157.21  TTOWN5       #DOM:AMERICA        #PRE

   EVERST *BROADCAST    NETLOGON SAM LOGON request from client
   EVERST *NETBIOS Mult NETLOGON SAM LOGON request from client
   EVERST CIMCON        NETLOGON SAM LOGON request from client
   EVERST TTOWN1        NETLOGON SAM LOGON request from client
   EVERST TTOWN2        NETLOGON SAM LOGON request from client
   EVERST TTOWN3        NETLOGON SAM LOGON request from client
   EVERST TTOWN4        NETLOGON SAM LOGON request from client

CAUSE

The LMHOSTS parser code in NetBT incorrectly stores IP Addresses when building the <Domain Name 0x1c> Group Name.

STATUS

Microsoft has confirmed this to be a problem in Windows NT version 3.5. A fix to this problem is in development, but has not been regression-tested and may be destabilizing in production environments. Microsoft does not recommend implementing this fix at this time. Contact Microsoft Product Support Services for more information on the availability of this fix.