Patent ID: 7568224

Claim:
A method for authenticating the source IP address of a Session Initiation Protocol (SIP) data packet sent over a network from a source having a source IP address to a destination, the method comprising: receiving the SIP data packet at the destination; decoding, at the destination, data of the received SIP data packet, including at least the source IP address of the received SIP data packet; encoding said data of the received SIP data packet into a cookie; sending, from the destination, an outgoing SIP message to the source IP address, wherein said outgoing SIP message contains said cookie and is configured to solicit a SIP response from the source; if the source does not respond to said outgoing SIP message, then designating the source IP address of the SIP data packet to be unauthenticated, otherwise: receiving, at the destination, said SIP response in reply to said outgoing SIP message; decoding, at the destination, data of said received SIP response, including at least said cookie and a sender IP address of said received SIP response; processing said data of said received SIP response to determine if said received SIP response is from the source IP address and is an authentic response to said outgoing SIP message; and if said received SIP response is from the source IP address and is an authentic response to said outgoing SIP message, then designating the source IP address of the SIP data packet to be authenticated.