Patent ID: 7958233

Claim:
A computer-implemented method for lawfully intercepting communication IP packets exchanged between a first terminal having a first IP address and a second terminal having a second IP address comprising: a first equipment in a first data network of a first telecommunications service provider assigning a third IP address corresponding to the first telecommunications service provider to the first terminal for use in a SDP (Session Description Protocol) connection field of SIP (Session Initiation Protocol) messages sent by the first terminal, establishing communication between the first and second terminals by exchanging SIP messages using an SIP proxy service of the first data network, the first equipment and/or a second equipment in the first data network receiving at least some of the communication IP packets sent from the first terminal, intercepting the communication IP packets in the first data network; and the first and/or second equipment in the first data network receiving from the first terminal encapsulated communication IP packets having an outer header containing the first IP address, the first and/or second equipment unpacking the encapsulated communication IP packets to remove the outer header before sending the communication IP packets to the second terminal.