Service licensing and maintenance for networks

A technique is disclosed that allows different computers in a network to create an identifier that uniquely identifies the network. The technique allows the unique identifier to be consistently created over time, regardless of the particular make up of the computing devices in the network at any particular point time. In some implementation, a computer within the network hosts the identification creation tool. In order to create a unique identifier for the network, the tool identifies each network adapter used by the host computer. Using this information, the tool identifies a gateway device used by the network adapter or adapters, and then determines the physical network address of that gateway device. For example, if the network is an Ethernet network, the tool will determine the medial access control (MAC) address for the gateway device. The tool then creates a unique identifier for the network based upon the physical address. The unique network identifier can then be used to associate the billing a usage fee, such as a licensing fee, with the network rather than with an individual computer within the network. Alternately or additionally, the unique network identifier can be used to maintain and support the gateway device for the network.