A method and apparatus for determining whether an alias (or entity name) is available for use in a communication system. A transmitting node or entity transmits a first signal including the alias over the communication system. The alias includes a zone name. If the transmitting node receives a reply signal to the first signal, then the alias is not available for use. Otherwise the alias is available for use. The transmitting node transmits the first signal to a first router connected to a first local network of the communication system. The first router forwards a second signal including the entity name from the first signal to other routers in the network until a second router connected to nodes having the zone name in the entity name is located. Each second router translates the second signal into a third signal which includes the alias, and using a first zone multicast address, multicasts the third signal to a first set of nodes. Each node of the first set of nodes determines whether the zone name contained within the alias is equal to a zone identifier for each node of the first set of nodes. Each node having the zone name determines whether the alias contained within the third signal is equal to alias information for the node. If an entity in the first set of nodes has the alias, then the entity transmits a reply signal, which includes its network address, to the transmitting node.