The home network is generally separated from the Internet, as it is made up of a private network due to security issues and the lack of IPv4 addresses space. Also, a user may want to move from a terminal to another terminal connected in the home network during communicating with people outside the home. In this case, people connected in the Internet, or another home network could not communicate the user at the home. These limitations prevent a SIP-capable device connected in the home network from communicating with another SIP-capable device connected in the Internet or the outside of the home network. To overcome the limitations, This paper proposes the Adaptive SIP Application Server System as a software architecture that a user inside of the home can communicate with people outside of the home when the home is composed of a private IP-based network. Moreover, the proposed architecture provides the session mobility that allows the user to maintain a media session even if changing the terminal inside of the home during the session established. The proposed system was implemented over a home server device which acts functionality as a connection point for transmitting IP packets between a home network and the Internet.