A server to which a terminal device is configured to be connected via a network , the server characterized by comprising: a server certificate generator to generate a server certificate including an IP address of the server on the network ; a generation commander configured to command the server certificate generator to generate the server certificate; a certificate storage configured to store the server certificate generated by the server certificate generator based on a command generated by the generation commander ; and a communicator configured to communicate with the terminal device using the server certificate stored in the certificate storage , wherein the generation commander comprises an address change determiner configured to determine whether the IP address of the server is changed in a startup or a reboot of the server or as often as a predetermined time period passes, in response to a determination by the address change determiner that the IP address of the server is changed, the generation commander is configured to command the server certificate generator to generate a server certificate including a new IP address of the server , the server certificate generator is configured to generate the server certificate based on a route certificate generated by a route certificate generator , the certificate storage is configured to store the route certificate generated by the route certificate generator and the server certificate generated by the server certificate generator , the communicator is configured to communicate with the terminal device using the route certificate and the server certificate that are stored in the certificate storage , and the generation commander is configured to command, in response to a change of the route certificate stored in the certificate storage , the server certificate generator to generate a new server certificate. a server certificate generator to generate a server certificate including an IP address of the server on the network ; a generation commander configured to command the server certificate generator to generate the server certificate; a certificate storage configured to store the server certificate generated by the server certificate generator based on a command generated by the generation commander ; and a communicator configured to communicate with the terminal device using the server certificate stored in the certificate storage , wherein the generation commander comprises an address change determiner configured to determine whether the IP address of the server is changed in a startup or a reboot of the server or as often as a predetermined time period passes, in response to a determination by the address change determiner that the IP address of the server is changed, the generation commander is configured to command the server certificate generator to generate a server certificate including a new IP address of the server , the server certificate generator is configured to generate the server certificate based on a route certificate generated by a route certificate generator , the certificate storage is configured to store the route certificate generated by the route certificate generator and the server certificate generated by the server certificate generator , the communicator is configured to communicate with the terminal device using the route certificate and the server certificate that are stored in the certificate storage , and the generation commander is configured to command, in response to a change of the route certificate stored in the certificate storage , the server certificate generator to generate a new server certificate. <EOS>