DOCUMENT:Q227812 21-OCT-2000 [winnt] TITLE :Only TCP/IP Can Be Bound to Virtual Network Adapter in WLBS Host PRODUCT :Microsoft Windows NT PROD/VER:WINDOWS:2000; winnt:4.0 OPER/SYS: KEYWORDS:kbenv kbnetwork ====================================================================== ------------------------------------------------------------------------------- The information in this article applies to: - Microsoft Windows NT Server, Enterprise Edition version 4.0 - Microsoft Windows 2000 Advanced Server - Microsoft Windows 2000 Datacenter Server ------------------------------------------------------------------------------- SUMMARY ======= When Windows Load Balancing Service (WLBS) hosts that are operating in Unicast mode are connected directly to a switch, WLBS hides the virtual media access control (MAC) address by default so that the switch does not map the MAC address to a port. This is necessary because traffic to the virtual IP (VIP) address must reach all WLBS cluster hosts. As indicated in the WLBS configuration documentation, only TCP/IP should be bound to the virtual network adapter. If another protocol is bound to the virtual network adapter, the other protocol may send frames out through the network adapter, not giving the WLBS driver a chance to mask the virtual MAC address. MORE INFORMATION ================ The Network Load Balancing (NLB) driver in Windows 2000 Advanced Server and Datacenter Server is implemented as a filter and other protocols are not able to bypass it. NLB is then able to mask the virtual MAC address. For additional information, please click the article number below to view the article in the Microsoft Knowledge Base: Q193602 Configuration Options for WLBS Hosts Connected to a Layer 2 Switches Additional query words: ====================================================================== Keywords : kbenv kbnetwork Component : WLBS Technology : kbWinNTsearch kbWinNT400xsearch kbwin2000AdvServ kbwin2000AdvServSearch kbwin2000DataServ kbwin2000DataServSearch kbWinNTSsearch kbWinNTSEntSearch kbWinNTSEnt400 kbWinNTS400xsearch kbwin2000Search kbWinAdvServSearch kbWinDataServSearch Version : WINDOWS:2000; winnt:4.0 Issue type : kbinfo ============================================================================= 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 2000.