Patent ID: 8825822

Claim:
A method of traversing a firewall in a private network of a calling party, said method comprising: receiving, by a SIP proxy in a public network, a SIP Invite request from a calling party; sending a first punch firewall request to a relay agent for the calling party to open a port in the firewall for sending SIP signaling messages from the SIP proxy, the first punch firewall request containing a public address for the SIP proxy and a calling party private SIP address obtained from the SIP Invite request; receiving a first punch response message from the relay agent, the first punch response message containing the public address of a port at the firewall opened for SIP signaling messages from the SIP proxy; forwarding the SIP Invite request from the SIP proxy to the called party; receiving a SIP response message responsive to the SIP Invite request at the SIP proxy; and forwarding the SIP response message from the SIP proxy to the public address of the port opened for SIP signaling messages.