Approaches for provisioning phones in packet voice networks are disclosed. One approach provides determining that an Internet Protocol (IP) phone has registered in a network; receiving a unique identifier of the IP phone; determining, based on the unique identifier of the IP phone, a user identifier of an individual user associated with the IP phone; generating a configuration for the IP phone based on the user identifier; and providing the configuration to the IP phone. Various approaches for deriving a user identifier based on the unique identifier of the phone are disclosed.