An approach that provides routing a SIP message to a proxy server of a called party in a communication network is provided. In one embodiment, there is a routing tool that assists in routing a session initiation protocol (SIP) message to a called party. The routing tool, including a receiving component, receives a SIP message of a user making a call in the network. The routing tool further includes a parsing component configured to parse the message to determine the domain of the called party and performs a table lookup using the domain of the called party in order to: retrieve a destination code; embed the destination code into the message; and route the message based on the destination code.