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.