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Q227880: Modifying TCP/IP Fields May Disable DHCP Relay Agent Service

Article: Q227880
Product(s): Microsoft Windows NT
Version(s): winnt:4.0,4.0 SP1,4.0 SP2,4.0 SP3,4.0 SP4
Operating System(s): 
Keyword(s): kbWinNT4sp6fix
Last Modified: 20-MAY-2002

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The information in this article applies to:

- Microsoft Windows NT Server version 4.0, Terminal Server Edition 
- Microsoft Windows NT Server versions 4.0, 4.0 SP1, 4.0 SP2, 4.0 SP3, 4.0 SP4 
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SYMPTOMS
========

When you run Microsoft Windows Server version 4.0 or later on a computer with
only one network adapter, changing any of the TCP/IP properties in Control Panel
causes the DHCP Relay Agent service running on that computer to become disabled.
Consequently, when you restart the computer, the DHCP relay agent service does
not start.

CAUSE
=====

This problem occurs because there was a restriction on having at least two
network adapters to use the DHCP Relay Agent service. This restriction has been
removed. DHCP Relay agent Service is usually run on multihomed computers.
However, in certain specific scenarios, such as an old router that does not
support DHCP RFC 1542, you may want the service configured on a computer with
only one network adapter to forward DHCP packets through unicast to a DHCP
server.

RESOLUTION
==========

To resolve this problem, obtain the latest service pack for Windows NT 4.0 or
the individual software update. For information on obtaining the latest service
pack, please go to:

- http://www.microsoft.com/Windows/ServicePacks/

-or-

- Q152734 How to Obtain the Latest Windows NT 4.0 Service Pack

For information on obtaining the individual software update, contact Microsoft
Product Support Services. For a complete list of Microsoft Product Support
Services phone numbers and information on support costs, please go to the
following address on the World Wide Web:

  http://support.microsoft.com/default.aspx?scid=fh;EN-US;CNTACTMS


STATUS
======

Microsoft has confirmed this to be a problem in the Microsoft products that are
listed at the beginning of this article. This problem was first corrected in
Windows NT Server version 4.0, Terminal Server Edition Service Pack 6.

Additional query words:

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Keywords          : kbWinNT4sp6fix 
Technology        : kbWinNTsearch kbWinNTSsearch kbWinNTS400sp4 kbWinNTS400sp2 kbWinNTS400search kbWinNT400search kbWinNTS400sp3 kbWinNTS400sp1 kbWinNTS400 kbNTTermServ400 kbNTTermServSearch
Version           : winnt:4.0,4.0 SP1,4.0 SP2,4.0 SP3,4.0 SP4
Hardware          : ALPHA x86
Issue type        : kbbug
Solution Type     : kbfix

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