Description of #MH Entry in Windows NT Lmhosts File (249866)


The information in this article applies to:

  • Microsoft Windows NT Server 4.0 Terminal Server Edition
  • Microsoft Windows NT Workstation 4.0
This article was previously published under Q249866

SUMMARY

This article describes how to use the multihomed (#MH) entry in the Windows NT Lmhosts file. You can use the #MH entry for adding multihomed static WINS mappings, but you cannot use it to provide multihomed NetBIOS name resolution.

MORE INFORMATION

You can use the #MH entry when you are importing an Lmhosts file into Windows Internet Naming Service (WINS). When you need to import a list of NetBIOS names and TCP/IP addresses into WINS for use as static mappings, you can use the "import Lmhosts file" functionality. Under these circumstances, you can use the #MH entry in the Lmhosts file to add a multihomed entry for a particular name. For example, assume that the following sample Lmhosts file is being used:

1.1.1.1 testsrv #MH
1.1.1.2 testsrv #MH

When you import this file into WINS, the following static mappings are added:

testsrv[00h] multihomed entry with addresses 1.1.1.1 and 1.1.1.2
testsrv[03h] multihomed entry with addresses 1.1.1.1 and 1.1.1.2
testsrv[20h] multihomed entry with addresses 1.1.1.1 and 1.1.1.2

You cannot use the #MH functionality when you are using the Lmhosts file to resolve names during normal NetBIOS name lookup tasks. For example, assume that the following sample Lmhosts file is being used:

testsrv 1.1.1.1 #PRE #MH
testsrv 10.10.10.2 #PRE #MH

When you load this file into the NetBIOS name cache, it shows two entries for each computer name for each service, but only the last IP address is used when NetBIOS name resolution attempts to resolve the name. The NetBIOS name cache appears as follows: 
                  NetBIOS Remote Cache Name Table

   Name                 Type        Host Address    Life (sec)
   ------------------------------------------------------------
   TESTSRV          <03> UNIQUE       1.1.1.1          -1
   TESTSRV          <00> UNIQUE       1.1.1.1          -1
   TESTSRV          <20> UNIQUE       1.1.1.1          -1
   TESTSRV          <03> UNIQUE       10.10.10.2       -1
   TESTSRV          <00> UNIQUE       10.10.10.2       -1
   TESTSRV          <20> UNIQUE       10.10.10.2       -1
However, if you then try to connect to \\Testsrv, only the last entry is used when you are trying to build a TCP session.
Modification Type:MajorLast Reviewed:6/29/2004
Keywords:kbenv kbinfo KB249866
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