IPX: Controlling NetBIOS Broadcasts Through NWLink

• Microsoft Windows NT Workstation versions 3.51 and 4.0
• Microsoft Windows NT Server versions 3.51 and 4.0

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.

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. Not 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 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)

   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)

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.