Message handling in a communications network

A method and apparatus for handling a Session Initiation Protocol message in a communications network. When a network node receives a Session Initiation Protocol message, which comprises Request-URI header, the node rewrites the Request-URI header in the SIP message, and adds information to the SIP message useable by a remote node to determine the current target address of the message. The SIP message is then sent to a further node. In this way, the remote node that receives the message can determine the current target in the SIP message, even if the target has been re-written in the Request-URI as the result of, for example, a translation or re-routing operation.