Microsoft KB Archive/157139

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Err Msg: The DHCP Client Was Unable to Obtain an IP Network...

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Q157139

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The information in this article applies to:


 * Microsoft Windows 95
 * Microsoft Windows 95 OEM Service Release, version 2.0

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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.

SYMPTOMS
When you attempt to pass IP broadcasts, such as DHCP, over a Token Ring transparent bridge, you may receive the following error message:

The DHCP client was unable to obtain an IP network address from a DHCP server.

Or, you may be unable to resolve names of computers on the other side of the bridge.

CAUSE
Windows 95-based computers set the Source Routing (SR) bit in all IP broadcast traffic by default. Transparent bridges may discard frames with Source Routing information when passing them to different media types (such as Ethernet).

RESOLUTION
This issue is resolved by the following updated file for Windows 95 and OEM Service Release 2 (OSR2), and later versions of this file:

  VIP.386  version 4.00.953  dated 09/19/96  66,734 bytes An updated version of this file is included in the Windows Sockets 2.0 update for Windows 95. For information on obtaining this update, see the following article in the Microsoft Knowledge Base:

"Q182108 Availability of Windows Sockets 2.0 for Windows 95"

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.

After installing the update, add the following registry value and set it to 0:

  HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\VxD\MSTCP

ArpAlwaysSourceRoute Value Type: String Valid Range: 0 or 1 (false or true) Default: 0 If this parameter is set to 1, TCP/IP transmits ARP queries with source routing enabled on Token Ring networks. By default, Microsoft TCP/IP transmits ARP queries without source routing first and retries with source routing enabled if no reply is received. Applying the fix referenced in this article and adding this parameter and setting it to 0 causes all IP broadcasts to be sent without source routing.

STATUS
Microsoft has confirmed this to be a problem in Microsoft Windows 95 and OEM Service Release 2 (OSR2). An update to address this problem is now available, but is not fully regression tested and should be applied only to computers experiencing this specific problem. Unless you are severely impacted by this specific problem, Microsoft does not recommend implementing this update at this time. Contact Microsoft Technical Support for additional information about the availability of this update.

This issue is resolved in Microsoft Windows 98.

MORE INFORMATION
For information about additional issues resolved by updates to this component, please see the following articles in the Microsoft Knowledge Base:

Q153749 No Single-Route Broadcast on Token Ring with Windows 95 TCP/IP

Q142543 Windows 95 Hangs with TCP/IP Routing Enabled For additional information about Windows 95 updates, please see the following article in the Microsoft Knowledge Base:

"Q161020 Implementing Windows 95 Updates" Additional query words:

Keywords : kbnetwork kbpolicy win95

Issue type : kbprb

Technology : kbWin95search kbOPKSearch kbWin95