The dedicated IP addresses in Network Load Balancing (NLB) must be properly configured and be able to contact individual NLB cluster hosts. If the dedicated IP address is not configured correctly, you cannot use it to manage the host or for other non-cluster-related communication.
Ensure consistent number of dedicated IP addresses and subnet masks
On all Network Load Balancing (NLB) cluster hosts, the dedicated IP addresses must have an equal number of subnet masks specified. If there are an unequal number, the NLB cluster will continue to operate, but the IP address that has no corresponding network mask will be ignored. To use this IP address, make sure that the number of IP addresses and network masks are the same.
To ensure that the number of dedicated IP addresses is the same as the number of subnet masks:
Click Start, click Administrative Tools, and then click Network Load Balancing Manager. You can also open NLB Manager by typing Nlbmgr at a command prompt.
If NLB Manager does not already list the cluster, connect to the cluster.
Right-click the host that you want to configure, and then click Host Properties.
Click the Host Parameters tab.
In IP address and Subnet mask, verify that for each dedicated IP address there is a corresponding subnet mask. If necessary, enter a valid dedicated IP address or subnet mask.