IPX: Controlling NetBIOS Broadcasts Through NWLink

ID: Q166878

The information in this article applies to:

Microsoft Windows NT Workstation versions 3.51, 4.0
Microsoft Windows NT Server versions 3.51, 4.0
Microsoft Windows 2000 Professional
Microsoft Windows 2000 Server
Microsoft Windows 2000 Advanced Server

IMPORTANT: This article contains information about editing the registry. Before you edit the registry, make sure you understand how to restore it if a problem occurs. For information about how to do this, view the "Restoring the Registry" Help topic in Regedit.exe or the "Restoring a Registry Key" Help topic in Regedt32.exe.

SUMMARY

This article explains how you can reduce the number of NetBIOS broadcasts issued by NWLinkNetBIOS (over the IPX\SPX Compatible Transport).

MORE INFORMATION

There are three registry entries that, if manipulated correctly, can reduce the number of NetBIOS broadcasts you are seeing from Windows NT Workstations and Windows NT Server computers. The long-range affect of this has not been tested. Whether this will have an adverse affect on the domain and browsing is not known at this time. These registry entries can be found in the Windows NT 3.51 Resource Kit on page 510. These registry entries are located under

HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\NWlnkNB \Parameters (The book says NWNBLink, this is incorrect).

NOTE: The above registry key is one path; it has been wrapped for readability.

WARNING: Using Registry Editor incorrectly can cause serious problems that may require you to reinstall your operating system. Microsoft cannot guarantee that problems resulting from the incorrect use of Registry Editor can be solved. Use Registry Editor at your own risk.

For information about how to edit the registry, view the "Changing Keys And Values" Help topic in Registry Editor (Regedit.exe) or the "Add and Delete Information in the Registry" and "Edit Registry Data" Help topics in Regedt32.exe. Note that you should back up the registry before you edit it.

The first of these entries is:


   BroadcastCount:REG_DWORD: 1 - 65535
   Specifies the number of times to send a broadcast. If Internet
   is set to 1, the BroadcastCount is doubled.
   Default: 3 (no entry = default)

This entry, as its name implies, determines the number of times a NetBIOS name query is sent out. When you attempt to connect to another computer through File Manager, Explorer, or a Net Use, this determines how many times Windows NT will send out a broadcast in an attempt to locate that particular computer. Changing this entry will change the number of broadcasts sent out in that query. This affects workgroup announcements and local master announcements in the same way.

This setting will not affect the <01><02>_MSBROWSE_<02><01> announcements you might see. That announcement is used by Master Browsers when their browse list is empty. It prompts all Master Browsers to announce themselves so that the Master Browser that sent the Find Name out can fill its browse list.

NOTE: The more workgroups and domains you have, the more of these <01><02>_MSBROWSE_<02><01> you will see along with workgroup announcements. You will see most announcements after a computer has been restarted. These will taper off to regular announcement intervals of every 12-15 minutes.

The second of these entries is:


   BroadcastTimeout:REG_DWORD: 1 - 65535 half-seconds
   Specifies the time between sending find-name requests. This value
   is not affected if Internet is set to 1.
   Default: 1 (no entry = default)

This entry is exactly as it sounds. If BroadcastCount is set to 3 and BroadcastTimeout is set to 1, you will get 3 broadcasts at approximately half-second intervals. Making this number larger will increase the time between broadcasts.

The third of these entries is:


   Internet:REG_DWORD: 0 or 1
   Specifies whether to change the packet type from 0x04 to 0x14
   (Novell WAN Broadcast).
   Default: 1 (true; no entry = default)

This entry causes all find-name broadcasts to go out as Type 0x04 or Type 0x14. Type 0x04 broadcasts will not be forwarded across routers. This has the same effect as turning off Type 20 broadcasts at the routers, which will disable browsing and connecting across the routers.

Browser announcements over an IPX host link are broadcast using a WAN broadcast because the browser component requests a 0x14 packet type. Setting Internet under the NWLNKNB registry key to 0 only affects the NetBIOS broadcasts. Even if the Internet entry in the registry is set to 0 (use packet type 0x04), Windows NT propagates a few type 0x14 frames. This is necessary for support for some applications that may require it.

Additional query words: WAN traffic reduce broadcasts netbios

Keywords : kbnetwork ntprotocol ntregistry NTSrvWkst
Version : WINDOWS:2000; winnt:3.51,4.0
Platform : WINDOWS winnt
Issue type : kbhowto