Microsoft KB Archive/264645

= IP Address Conflict Switching Between Unicast and Multicast NLB Cluster Mode =

Article ID: 264645

Article Last Modified on 3/1/2007

-

APPLIES TO


 * Microsoft Windows 2000 Advanced Server

-



This article was previously published under Q264645



SYMPTOMS
After you change the Network Load Balancing cluster mode from or to Unicast or Multicast in a cluster with two or more members, the following error message may appear:

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.



CAUSE
The cluster Unicast and Multicast media access control (MAC) addresses are different. The cluster MAC address changes on the host if you change the cluster mode to be different from the cluster MAC address on the other cluster host(s).



RESOLUTION
Remove the cluster IP address from TCP/IP properties before you change the cluster host. Before you add the IP address again after making the change, make sure that all cluster hosts are configured to use the same mode (Unicast or Multicast).



STATUS
This behavior is by design.



MORE INFORMATION
The IP address conflict error message is reported because two MAC addresses claim the same IP address.

Keywords: kbnetwork kbnlb kbprb KB264645

-

[mailto:TECHNET@MICROSOFT.COM Send feedback to Microsoft]

© Microsoft Corporation. All rights reserved.