DOCUMENT:Q227880 20-MAY-2002 [winnt] TITLE :Modifying TCP/IP Fields May Disable DHCP Relay Agent Service PRODUCT :Microsoft Windows NT PROD/VER:winnt:4.0,4.0 SP1,4.0 SP2,4.0 SP3,4.0 SP4 OPER/SYS: KEYWORDS:kbWinNT4sp6fix ====================================================================== ------------------------------------------------------------------------------- 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 ------------------------------------------------------------------------------- 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: ====================================================================== 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 ============================================================================= THE INFORMATION PROVIDED IN THE MICROSOFT KNOWLEDGE BASE IS PROVIDED "AS IS" WITHOUT WARRANTY OF ANY KIND. MICROSOFT DISCLAIMS ALL WARRANTIES, EITHER EXPRESS OR IMPLIED, INCLUDING THE WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. IN NO EVENT SHALL MICROSOFT CORPORATION OR ITS SUPPLIERS BE LIABLE FOR ANY DAMAGES WHATSOEVER INCLUDING DIRECT, INDIRECT, INCIDENTAL, CONSEQUENTIAL, LOSS OF BUSINESS PROFITS OR SPECIAL DAMAGES, EVEN IF MICROSOFT CORPORATION OR ITS SUPPLIERS HAVE BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGES. SOME STATES DO NOT ALLOW THE EXCLUSION OR LIMITATION OF LIABILITY FOR CONSEQUENTIAL OR INCIDENTAL DAMAGES SO THE FOREGOING LIMITATION MAY NOT APPLY. Copyright Microsoft Corporation 2002.