Patent ID: 7274684

Claim:
A method for processing at least one session initiation protocol (SIP) or H.323 packet over a network, comprising the steps of: receiving said at least one SIP or H.323 packet; and mapping said at least one SIP or H.323 packet from a public internet protocol (IP) address field to a private IP address field and a public transaction identification (TID) number to a private port TID number using an application layer gateway (ALG) database; wherein said mapping step comprises the steps of: receiving said at least one SIP or H.323 packet from a wide area network (WAN) comprising said public IP address field; storing said public IP address field and said public TID number in said ALG database and assigning said private TID number and inserting said private TID number into said ALG database; determining whether said public TID number and said mapped private TID number and said mapped private IP address field exists in said ALG database, wherein if said public TID number or said mapped private TID number or said mapped private IP address field does not exist in said ALG database, then said at least one SIP or H.323 packet is dropped; and wherein if said public TID number or said mapped private TID number or said mapped private IP address field does exist in said ALG database, then replacing said public IP address field with said private IP address field and replacing said public TID number with said private TID number, and transmitting said at least one SIP or H.323 packet to a local area network (LAN) comprising said private IP address field.