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December 20, 2000 No. 98

Configuring Lana Numbers in NT 4.0 and Windows 2000

This Tech Note is an addendum to, and should be used in conjunction with, Tech Note 92 "Running NPL in a Windows NT environment".

Occasionally, even if properly configured, the RunTime may experience difficulty authenticating with an NT/Windows 2000 server from some NT/Windows 2000 workstations, resulting in an erroneous "Number of Authorized users exceeded", error message.   This problem is typically related to the LANA (LAN Adapter) number configuration of NetBIOS on the workstation, if the default LANA number, zero, is bound to a wide-area network.  Note that any time you have what looks like a valid default LANA number and it doesn't actually work, the only message you're going to get is the 'user limit exceeded' message.  Unfortunately, it is beyond the NPL RunTime to determine why NetBIOS isn't working.

To correct this problem on an NT 4.0 system

1.Log in as administrator

2. Open Properties of Network Neighborhood (or open the Control Panel/ Network applet).

3. Click the Services Tab.

4. Click on NetBIOS Interface.

5. Click the Properties... Button.

6. The network route associated with Lana number 000 should be:

NwlnkNb-> NwlnkIpx


Nbf->(your network Card Name).

   If Lana number 000 is set to “NetBT->(something), it needs to be adjusted.

Niakwa strongly recommends that the network route associated with Lana number 000 be “NwlnkNb-> NwlnkIpx”.  This is consistent with past recommendations for Windows for Workgroups.  However, before adjusting Lana 000, you should check a working NT system to make sure you are in sync with other NT systems on the network.

WARNING:     Under no circumstances use a network route containing NetBT or Wan in the name.

To correct the Lana Number:

1. Highlight the 000, and click the Edit Button.

2. Change the number to a high value  (say, 9).

3. Highlight the number next to NwlnkNb-> NwlnkIpx, and edit this to say 0.  To keep things tidy, you could change the 9 to keep all the numbers sequential.  After you close the Networks dialog, you will need to restart the machine for the change to take effect.

To correct this problem on a Windows 2000 system

The capability to view and make adjustments to the LANA numbers was removed from Windows 2000.  The operating system assigns the LANA numbers automatically. Microsoft supplies a command line utility that can be used to view and configure LANA numbers.   This utility is available for download from:


- Go to Product updates and search using Update Type - Management and Deployment Tools, and Platform Windows 2000.

WARNING: DO NOT try to install or use LANACFG.EXE on any other operating system but Windows 2000.  It’s not exactly clear why, but Microsoft warns against it.

Lanacfg.exe is a command line utility, it doesn't have the graphical interface that the Win NT 4.0 utility had.  With this utility you type commands to do what you used to do graphically in order to check the order, and modify it to get LANA #0 to be the one that goes to the correct NetBIOS type (usually the one that uses the NWLink NetBIOS path).


Place LANACFG.EXE into the WINNT\SYSTEM32 subdirectory.  Open a command prompt (previously called a DOS prompt) and change directories to the WINNT\SYSTEM32 directory.   If you run lanacfg with no parameters, you will be presented with 4 command line options to use.

showlanapaths   - Show bind paths and component descriptions for each exported lana

setlananumber   - Change the lana number of a bind path

rewritelanainfo - Verify and write out lana info to the registry

showlanadiag    - Show lana diagnostic info

If you run "lanacfg showlanapaths", the LANA number information will display to the screen. However if you run  "lanacfg showlanapath>lanaconfig.txt", a text file called lanaconfig.txt will be created with the same information.  The 'lanacfg showlanapaths' will basically give you a list of what LANA numbers are configured, and where they go.  The output will look something like:

Lana:   3

-->NWLink NetBIOS

Lana:   0

-->WINS Client(TCP/IP) Protocol-->Internet Protocol (TCP/IP)-->NETGEAR FA310TX Fast Ethernet Adapter (NGRPCI)

In the example, there are 2 LANA numbers, number 3 going to NWLink and number 0 going through TCP/IP.  To change the lana numbers to a the recommended configuration, you need to do a series of :

lanacfg setlananumber OldLanaNumber NewLanaNumber

 commands to reorder them.  In the example, after doing:

lanacfg setlananumber 0 1

lanacfg setlananumber 3 0

The output from 'lanacfg showlanapaths' would look more like:

Lana:   0

-->NWLink NetBIOS

Lana:   1

-->WINS Client(TCP/IP) Protocol-->Internet Protocol (TCP/IP)-->NETGEAR FA310TX Fast Ethernet Adapter (NGRPCI)

which puts the NWlink as the default lana number (LANA 0).

The above example is a simple one.  More protocols, network cards, and dialup “adapters” will increase the complexity of the process.


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