Remote system, remote connection method and computer readable storage medium

A remote connection method for implementing remote connection to a production device by an external terminal, the method comprising:

• relaying, by a server device, communication between the production device and the external terminal via a local area network including the production device and a gateway, the local area network and the server device being connected via a wide area network, the server device being situated outside of the local area network, the external terminal being an information communication device;
• permitting connection from an inside of the local area network to an outside of the local area network and rejecting all connection from the outside of the local area network to the inside of the local area network, by a network device situated between the gateway and the server device and installed at (a) a connection point of the local area network and the wide area network or (b) between (i) the connection point and (ii) the production device;
• requesting, by the gateway, the server device to establish a first session between the gateway and the server device;
• establishing, by the server device the first session in response to a request for establishing the first session;
• checking, by the server device, whether device identification information included in a device connection request is included in device information when the server device receives, from the external terminal, the device connection request including the device identification information for identifying a target production device designated from the external terminal, wherein the device identification information for identifying the production device is associated with gateway identification information for identifying the gateway connectable to the production device in the device information;
• establishing, by the server device, a second session between the external terminal and the server device when the device identification information included in the device connection request is included in the device information as a result of the checking;
• acquiring, by the server device, from the device information, the gateway identification information corresponding to the device identification information included in the device connection request;
• linking, by the server device the first session and the second session;
• and
• relaying, by the server device, the communication between the external terminal and the production device by using the first session and the second session that are linked with each other.

A non-transitory computer readable storage medium storing a program for operating a server device to be used in a remote system that implements remote connection to a production device by an external terminal, the program causing the server device to execute:

• relaying, by a server device, communication between the production device and the external terminal via a local area network including the production device and a gateway, the local area network and the server device being connected via a wide area network, the server device being situated outside of the local area network, the external terminal being an information communication device;
• storing device information in which identification information for identifying the production device is associated with gateway identification information for identifying the gateway connectable to the production device;
• receiving, from the external terminal, a device connection request including device identification information for identifying a target production device designated from the external terminal;
• checking whether the device identification information included in the device connection request is included in the device information;
• establishing a first session in response to a request, from the gateway, for establishing the first session between the gateway and the server device, the request for establishing the first session being received via a network device situated between the gateway and the server device and installed at (a) a connection point of the local area network and the wide area network or (b) between (i) the connection point and (ii) the production device, the network device permitting connection from an inside of the local area network to an outside of the local area network and rejecting all connection from the outside of the local area network to the inside of the local area network;
• establishing a second session between the external terminal and the server device when the device identification information included in the device connection request is included in the device information as a result of the checking;
• acquiring, from the device information, the gateway identification information corresponding to the device identification information included in the device connection request;
• linking the first session and the second session, the first session being established between the server device and the gateway that corresponds to the acquired gateway identification information;
• and
• relaying communication between the external terminal and the production device by using the first session and the second session that are linked with each other.