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Q156384: Control of Source Routing on Token Ring IP Broadcasts

Article: Q156384
Product(s): Microsoft Windows NT
Version(s): winnt:4.0
Operating System(s): 
Keyword(s): kbnetwork
Last Modified: 09-AUG-2001

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The information in this article applies to:

- Microsoft Windows NT Workstation version 4.0 
- Microsoft Windows NT Server version 4.0 
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SYMPTOMS
========

Attempts to pass IP broadcasts, such as DHCP traffic, over a Token Ring
transparent bridge may fail. This failure results in various symptoms, such as
the inability to obtain an IP address via DHCP, or the inability to resolve the
names of computers on the other side of the bridge.

CAUSE
=====

Computers running Microsoft Windows NT set the source routing 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
==========

WARNING: Using Registry Editor incorrectly can cause serious, system-wide
problems that may require you to reinstall Windows NT to correct them. Microsoft
cannot guarantee that any problems resulting from the use of Registry Editor can
be solved. Use this tool at your own risk.

In order to configure a computer running Microsoft Windows NT version 4.0 to send
IP broadcasts without source routing, the following Registry parameter must be
added and set to 0:

ArpAlwaysSourceRoute
Key: HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services
Tcpip\Parameters
Value Type: REG_DWORD - Boolean
Valid Range: 0,1 (False or True)
Default: 0 (False)

When you set this parameter to 1, you force TCP/IP to transmit ARP queries with
source routing enabled on token ring networks. By default, the stack transmits
ARP queries without source routing first, and retries with source routing
enabled if no reply was received. After applying the hotfix referenced in this
article, adding this parameter and setting it to 0 will cause all IP broadcasts
to be sent without source routing.

STATUS
======

Microsoft has confirmed this to be a problem in Windows NT version 4.0. A
supported fix is now available, but has not been fully regression-tested and
should be applied only to systems experiencing this specific problem. Unless you
are severely impacted by this specific problem, Microsoft recommends that you
wait for the next Service Pack that contains this fix. Contact Microsoft
Technical Support for more information.


Additional query words: prodnt

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Keywords          : kbnetwork 
Technology        : kbWinNTsearch kbWinNTWsearch kbWinNTW400 kbWinNTW400search kbWinNT400search kbWinNTSsearch kbWinNTS400search kbWinNTS400
Version           : winnt:4.0

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