vCenter Server 4.1 uses Microsoft ADAM/AD LDS to enable Linked Mode, which uses the Windows RPC port mapper to open RPC ports for replication. When you install vCenter Server in Linked Mode, the firewall configuration on any network-based firewalls must be modified.

Incorrect configuration of firewalls can cause licenses and roles to become inconsistent between instances.

Configure Windows RPC ports to generically allow selective ports for machine-to-machine RPC communication.

Choose one of the following methods.

Change the registry settings. See http://support.microsoft.com/kb/154596/en-us.

Use Microsoft's RPCCfg.exe tool. See http://support.microsoft.com/kb/908472/en-us.