DOCUMENT:Q156974 10-AUG-2001 [crossnet] TITLE :IBM 6611 Routers May Generate Invalid DHCP Frames PRODUCT :Windows for Workgroups and Windows NT Networking Issues PROD/VER:WINDOWS:95; winnt:3.51,4.0 OPER/SYS: KEYWORDS:kb3rdparty kberrmsg kbnetwork win95 ====================================================================== ------------------------------------------------------------------------------- The information in this article applies to: - Microsoft Windows NT Workstation versions 3.51, 4.0 - Microsoft Windows NT Server versions 3.51, 4.0 - Microsoft Windows 95 ------------------------------------------------------------------------------- SYMPTOMS ======== Your Dynamic Host Configuration Protocol (DHCP) clients that are on the opposite side of an IBM 6611 router from their DHCP Server may receive one of the following error messages when they attempt to lease an IP address: Windows NT DHCP Client ---------------------- The DHCP client could not obtain an IP address. If you want to see DHCP messages in the future, choose YES, otherwise choose NO. Windows 95 DHCP Client ---------------------- This DHCP client was unable to obtain an IP network address from a DHCP server. CAUSE ===== Some versions of software for the IBM 6611 router create and forward invalid frames when the router is acting as an RFC 1542 BOOTP relay agent. Specifically, the frames are invalid because their IP header contains a Source IP Address of 0.0.0.0, rather than the IP address of the router. These invalid frames are silently discarded by the Windows NT TCP/IP stack and are not passed to the DHCP service on the server. RESOLUTION ========== To correct this problem, contact IBM and request an upgrade to the IBM 6611 router software. The product included here is manufactured by a vendor independent of Microsoft; we make no warranty, implied or otherwise, regarding the product's performance or reliability. MORE INFORMATION ================ Per section 4.2.2.11 of RFC 1812 (Requirements for IP Version 4 Routers), a Source IP Address of 0.0.0.0 "MUST NOT be used as a source address by routers, except the router MAY use this as a source address as part of an initialization procedure (for example, if the router is using BOOTP to load its configuration information)." In the situation described here, the IBM 6611 router is not in the process of determining its own configuration, and therefore, the frames it generates with a Source IP Address of 0.0.0.0 are invalid. Additional query words: ====================================================================== Keywords : kb3rdparty kberrmsg kbnetwork win95 Technology : kbWinNTsearch kbWinNTWsearch kbWinNTW400 kbWinNTW400search kbWinNT351search kbWinNT400search kbWinNTW351search kbWinNTW351 kbWinNTSsearch kbWinNTS400search kbWinNTS400 kbWinNTS351 kbWinNTS351search kbWin95search kbZNotKeyword3 Version : WINDOWS:95; winnt:3.51,4.0 Issue type : kbprb ============================================================================= 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.