In a Network Load Balancing (NLB) cluster, port rules are configured to control how each port's cluster network traffic is handled. The NLB cluster may fail to converge unless each port rule has a unique host priority (a number between 1 and 32), the port rules are consistent on all cluster hosts, you are using the proper number of port rules, and the virtual IP address is specified in a valid IPv4 or IPv6 address format.
Check that the virtual IP address for the port rule is valid
If the virtual IP address for a port rule is not in a valid format, the Network Load Balancing (NLB) cluster will converge and operate normally, but the port rule will be ignored. You should check that the virtual IP address is specified in a valid IPv4 or IPv6 address format.
To check that the virtual IP address for a port rule is in a valid IPv4 or IPv6 format:
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 cluster, and then click ClusterProperties.
Click the Port Rules tab.
In the Defined port rules list, click a rule, and then click Edit. Verify that the IPv4 or IPv6 address is correctly formatted. IPv4 addresses use the standard Internet dotted notation (for example, w.x.y.z). IPv6 addresses use 16-byte addresses, typically expressed in colon-hexadecimal notation. Colon-hexadecimal notation uses eight 4-digit hexadecimal numbers, with colons separating the 16-bit blocks (the 4-digit numbers). To manage addresses more easily, IPv6 suppresses leading zeros and compresses a single contiguous all-zero 16-bit block, represent the contiguous block with two colons (::). This is known as double-colon compression. An example of an IPv6 address with leading zeros suppressed is: FEC0:0:0:0:2AA:FF:FE3F:2A1C