Limit switch port flooding

Applies To: Windows Server 2003, Windows Server 2003 R2, Windows Server 2003 with SP1, Windows Server 2003 with SP2

To limit switch port flooding

If multicast support has been enabled during setup, open Network Load Balancing Manager.
If Network Load Balancing Manager does not already list the cluster, connect to the cluster.
Right-click the cluster, and then click Cluster Properties.
On the Cluster Parameters tab, click the IGMP multicast check box to enable Internet Group Management Protocol (IGMP) support on all hosts in the cluster.

Important

To start Network Load Balancing Manager, open a Command prompt. From the command window, type NLBMgr, and then press ENTER.

Notes

When using Network Load Balancing Manager, you must be a member of the Administrators group on the host that you are configuring, or you must have been delegated the appropriate authority. As a security best practice, consider using Run as to perform this procedure. If you are configuring a cluster or host by running Network Load Balancing Manager from a computer that is not part of the cluster, you do not need to be a member of the Administrators group on that computer. For more information, see Default local groups, Default groups, and Using Run as.
To start Network Load Balancing Manager, open a Command prompt. From the command window, type NLBMgr, and then press ENTER.
To start Network Load Balancing Manager, open a Command prompt. From the command window, type NLBMgr, and then press ENTER.
If the cluster hosts are directly connected to a hub to receive client requests and IGMP support is not enabled, incoming client traffic is automatically sent to all switch ports, and may produce switch flooding.
You can only enable IGMP support when your cluster is configured for multicast mode. To enable multicast mode, see "Enable multicast support" in Related Topics below.
Windows NT Load Balancing Service (WLBS) is the former name of Network Load Balancing in Windows NT 4.0. For backward compatibility reasons, WLBS continues to be used in certain instances.

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