DOCUMENT:Q174929 09-AUG-2001 [crossnet] TITLE :No Response to ARP Causes Duplicate IP Addresses on Network PRODUCT :Windows for Workgroups and Windows NT Networking Issues PROD/VER:WinNT:4.0;Windows:3.11,95 OPER/SYS: KEYWORDS:kbnetwork kbWinNT400sp4fix win95 ====================================================================== ------------------------------------------------------------------------------- The information in this article applies to: - Microsoft Windows NT Workstation version 4.0 - Microsoft Windows NT Server version 4.0 - Microsoft Windows for Workgroups version 3.11 - Microsoft TCP/IP-32 for Windows for Workgroups, versions 3.11, 3.11a, 3.11b - Microsoft Windows 95 - Microsoft Windows NT Server version 4.0, Terminal Server Edition ------------------------------------------------------------------------------- SYMPTOMS ======== You may experience one of the following error messages, depending on the client: Windows NT 4.0 -------------- System Process - System Error The system has detected an IP address conflict with another system on the network. The local interface has been disabled. More details are available in the system event log. Consult your network administrator to resolve the conflict. Windows 95 ---------- Windows The system has detected a conflict for IP address a.b.c.d with the system having hardware address 11:11:11:11:11:11. The interface has been disabled. Windows for Workgroups ---------------------- Windows The system has detected a conflict for IP address a.b.c.d with the system having hardware address 00:00:00:00:00:00. The local interface has been disabled. CAUSE ===== The Microsoft networking clients listed above do not respond to an address resolution protocol (ARP) request when the ARP sender's IP address is 0.0.0.0. This causes a problem with Dynamic Host Configuration Protocol (DHCP) environments, which may result in duplicate IP addresses on the network. RESOLUTION ========== To resolve this problem, obtain the latest service pack for Windows NT 4.0 or Windows NT Server 4.0, Terminal Server Edition. For additional information, please see the following article in the Microsoft Knowledge Base: Q152734 How to Obtain the Latest Windows NT 4.0 Service Pack STATUS ====== Microsoft has confirmed this to be a problem in Windows NT 4.0 and Windows NT Server 4.0, Terminal Server Edition. This problem was first corrected in Windows NT 4.0 Service Pack 4.0 and Windows NT Server 4.0, Terminal Server Edition Service Pack 4. Microsoft has confirmed this to be a problem in the Microsoft products listed at the beginning of this article. We are researching this problem and will post new information here in the Microsoft Knowledge Base as it becomes available. MORE INFORMATION Non-Microsoft DHCP clients fill in the sender's IP address with 0.0.0.0 when using ARP to check if the DHCP lease that it has been offered is a duplicate address on the network. Because the Microsoft clients above do not respond to this ARP, it is possible to end up with duplicate addresses on the network. The following information is taken from RFC1541: The client may issue an ARP request for the suggested request. When broadcasting an ARP request for the suggested address, the client must fill in its own hardware address as the sender's hardware address, and 0 as the sender's IP address, to avoid confusing ARP caches in other hosts on the same subnet. If the network address appears to be in use, the client sends a DHCPDECLINE message to the server and waits for another DHCPOFFER. As the client does not have a valid network address, the client must broadcast the DHCPDECLINE message. Additional query words: ====================================================================== Keywords : kbnetwork kbWinNT400sp4fix win95 Technology : kbWinNTsearch kbWinNTWsearch kbWinNTW400 kbWinNTW400search kbWinNT400search kbWinNTSsearch kbWinNTS400search kbWinNTS400 kbNTTermServ400 kbNTTermServSearch kbAudDeveloper kbWin95search kbTCPIPSearch kbWFWSearch kbZNotKeyword3 kbWFW311 kbTCPIP311 kbTCPIP311a kbTCPIP311b Version : WinNT:4.0;Windows:3.11,95 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 2001.