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Q103444: RAS Server 64 Port Limitation Information

Article: Q103444
Product(s): Microsoft Windows NT
Version(s): 3.1
Operating System(s): 
Keyword(s): kbnetwork
Last Modified: 08-AUG-2001

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The information in this article applies to:

- Microsoft Windows NT Advanced Server, version 3.1 
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Remote Access Service (RAS) for Windows NT Advanced Server does NOT
prevent administrators from configuring more than 64 dial-in ports.
However, the system will not support more than 64 simultaneous
incoming connections. Attempting to do this results in unpredictable
behavior. Microsoft does not support any attempt to exceed 64
simultaneous configured ports.

MORE INFORMATION
================

RAS requires that a NetBIOS LANA number be assigned for each dial-in and each
dial-out port. If a port is configured for both, it requires two LANAs. Port
types are assigned in the Network Control Panel application RAS Configuration
screen.

  Port type                # of LANAs
  -----------------------------------
  Dial-in                      1
  Dial-out                     1
  Dial-in and Dial-out         2

Windows NT has a fixed limit of 72 total NetBIOS LANAs. You should configure all
your RAS ports to consume less than 64 LANAs (see the above chart). The
remaining eight LANAs are generally set aside for use with other network
protocol bindings.

This explains why when you look at the NetBIOS configuration in the Network
Control Panel application, you will sometimes see RAS taking up more LANAs than
there are COM ports installed. For example, if you have a Windows NT Advanced
Server with two internal COM ports and you have configured both ports for
dial-in and one port for both dial-in and dial-out, when you look at the NetBIOS
configuration, you will see three LANAs assigned to RAS bindings.

For more information, query on the following word in the Microsoft Knowledge
Base:

  lana

Additional query words: prodnt

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Keywords          : kbnetwork 
Technology        : kbWinNTsearch kbWinNTAdvSerSearch kbWinNTAdvServ310 kbWinNT310Search
Version           : 3.1

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