RoutedNetworks.txt   [plain text]

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!== RoutedNetworks.txt for Samba release 2.2.0-alpha3 24 Mar 2001
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#NOFNR Flag in LMHosts to Communicate Across Routers

  Last reviewed: May 5, 1997 
  Article ID: Q103765 
  The information in this article applies to: 

       Microsoft Windows NT operating system version 3.1 
       Microsoft Windows NT Advanced Server version 3.1 

  SUMMARY

  Some of the LAN Manager for UNIX and Pathworks servers may have
problems in communicating across routers with
  Windows NT workstations. The use of #NOFNR flag in the LMHosts
file solves the problem. 

  MORE INFORMATION

  When you are communicating with a server across a router in a IP
routed environment, the LMHosts file is used to
  resolve Workstation name-to-IP address mapping. The LMHosts
entry for a remote machine name provides the IP
  address for the remote machine. In Lan Manager 2.x, providing
the LMHosts entry eliminates the need to do a Name
  Query broadcast to the local domain and instead a TCP session is
established with the remote machine. Windows NT
  performs the same function in a different way. 

  When an LMHosts entry exists for a remote server, Windows NT
will not send a Name Query broadcast to the local
  subnet and instead send a directed Name Query to the remote
server. If the remote server does not respond to the Name
  Query, further communications (TCP SYN, and so on) will not take
place. This was done to eliminate the performance
  issues when trying to connect to a remote machine when it was
not available (down). 

  Some of the older LAN Manager for UNIX and DEC Pathworks servers
do not respond to directed Name Queries sent
  by Windows NT. In that case, the users will see an error 53
(Path not found), even though they have specified the
  LMHosts entries correctly. A new LMHosts flag #NOFNR was added
to solve this problem. By specifying the
  #NOFNR flag on the same line where the name resolution
information for the server is provided, the directed Name
  Query can be avoided. For example: 

     130.20.1.1   mylmxserver   #PRE  #NOFNR


  Note that this will only apply to mylmxserver and not to any
other entries in the LMHosts file. To set
  a global flag, an entry could be added in the registry. To
completely remove any directed Name
  Queries sent from a Windows NT machine, create the following
value in
 
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Nbt\Parameters: 

     NoDirectedFNR   REG_DWORD   1


  This will cause the directed Name Queries to not go out for any