System and Non-Transitory Computer-Readable Medium

A system comprising:

• a communication control device configured to be connectable to an external network;
• a first communication device configured to be connectable to a first internal network, the first internal network being connected to the external network;
• and
• a second communication device configured to be connectable to a second internal network, the second internal network being connected to the external network, wherein
• the communication control device comprises:
• a processor;
• and
• a memory storing computer-readable instructions, the computer-readable instructions, when executed by the processor of the communication control device, causing the communication control device to perform operations comprising:
• acquiring first network information that identifies the first internal network, and second network information that identifies the second internal network;
• deciding a first method based on the first network information and the second network information, the first method indicating a method of transmission from the first communication device to the second communication device, and of transmission from the second communication device to the first communication device;
• and
• first sending information indicating the first method to the first communication device and the second communication device, wherein
• the first communication device comprises:
• a processor;
• and
• a memory storing computer-readable instructions, the computer-readable instructions, when executed by the processor of the first communication device, causing the first communication device to perform operations comprising:
• second sending the first network information to the communication control device;
• first receiving the information indicating the first method from the communication control device;
• and
• first communicating with the second communication device using the first method, based on the received information indicating the first method,
• and wherein
• the second communication device comprises:
• a processor;
• and
• a memory storing computer-readable instructions, the computer-readable instructions, when executed by the processor of the second communication device, causing the second communication device to perform operations comprising:
• third sending the second network information to the communication control device;
• second receiving the information indicating the first method from the communication control device;
• and
• second communicating with the first communication device using the first method, based on the received information indicating the first method.