Only TCP/IP Should Be Bound to Virtual Network Adapter in WLBS Host

ID: Q227812

This article discusses a Beta release of a Microsoft product. The information in this article is provided as-is and is subject to change without notice.

No formal product support is available from Microsoft for this Beta product. For information about obtaining support for a Beta release, please see the documentation included with the Beta product files, or check the Web location from which you downloaded the release.

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
Version : WINDOWS:2000; winnt:4.0
Platform : WINDOWS winnt
Issue type : kbinfo