DOCUMENT:Q306378 08-MAY-2002 [winnt] TITLE :SNMP sends traps from last bound IP address on interface PRODUCT :Microsoft Windows NT PROD/VER::4.0 OPER/SYS: KEYWORDS:kbWinNT400PreSP7Fix ====================================================================== ------------------------------------------------------------------------------- The information in this article applies to: - Microsoft Windows NT Server version 4.0 - Microsoft Windows NT Workstation version 4.0 ------------------------------------------------------------------------------- SYMPTOMS ======== If your computer's network adapter is configured with one or more virtual IP addresses in addition to its primary IP address, and is also running the SNMP service, you may see in a network trace that the computer uses the last-bound virtual IP address as the source IP address in any SNMP trap frames that are generated by the computer (instead of the adapter's primary IP address). This can cause connectivity problems if the computer is part of a Windows Load Balancing Service (WLBS) server cluster. CAUSE ===== This issue occurs because SNMP selects the first IP address in the list of IP addresses that are returned by TCP/IP; this is always a virtual IP address if one or more virtual IP addresses are configured. The hotfix that is described in this article corrects this problem so that SNMP always selects a primary IP address for use as the IP source address in SNMP traps. RESOLUTION ========== A supported fix is now available from Microsoft, but it is only intended to correct the problem described in this article and should be applied only to systems experiencing this specific problem. To resolve this problem, contact Microsoft Product Support Services to obtain the fix. 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 NOTE: In special cases, charges that are normally incurred for support calls may be canceled, if a Microsoft Support Professional determines that a specific update will resolve your problem. Normal support costs will apply to additional support questions and issues that do not qualify for the specific update in question. The English version of this fix should have the following file attributes or later: Date Time Size File name Platform ------------------------------------------------- 17-Sep-2001 11:15 24,848 Snmpapi.dll Intel NOTE: Because of file dependencies, this hotfix requires Microsoft Windows NT 4.0 Service Pack 6a (SP6a). WORKAROUND ========== To work around this issue, install another network adapter in the computer and configure it so that it uses only a primary IP address and is the first network adapter in the TCP/IP binding order. SNMP then selects the unique primary IP address of this first adapter as the source IP address in its trap frames. The other network adapter can then be dedicated for use in a WLBS cluster if required. STATUS ====== Microsoft has confirmed this to be a problem in the Microsoft products that are listed at the beginning of this article. Additional query words: ====================================================================== Keywords : kbWinNT400PreSP7Fix Technology : kbWinNTsearch kbWinNTWsearch kbWinNTW400 kbWinNTW400search kbWinNT400search kbWinNTSsearch kbWinNTS400search kbWinNTS400 Version : :4.0 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.