Patent attributes
An internal terminal that connects to a DNS server, the server storing and managing a telephone number for communication and an external NAPTR record, the internal terminal including: a terminal communication controller that accesses the DNS server and notifies the DNS server of a telephone number for the communication; a terminal-side controller that obtains, when the DNS server is informed of the communication telephone number, an external NAPTR record being corresponding to the communication telephone number; an IP service presence determination unit that determines whether the external NAPTR record has function service information related to IP communication; and a display that displays the available IP communication service function of the destination corresponding to the communication telephone number, when it is determined that the external NAPTR record has the IP communication service function.