Network switch

A network switch connected to a plurality of communication lines and configured to relay data between the plurality of communication lines, the network switch comprising:

• a table record circuit configured to, for each of communication devices connected to the plurality of communication lines, record an address solution table configured to record a plurality of address information for mutually identifying each of the communication devices by a plurality of protocols;
• an information addition circuit configured to add new address information for a new communication device based on an address solution data to the address information table, when receiving the address solution data having a preset format for the new communication device in a case where the new address information for the new communication device is not recorded in the address solution table;
• a relay circuit configured to relay the data other than the address solution data by utilizing the address solution table when receiving the data;
• and
• a rewrite circuit configured to rewrite at least one of the address solution table or propriety information in accordance with an external instruction output from an external device positioned outside the corresponding network switch to the corresponding network switch,
• wherein:
• the address solution table includes the propriety information indicating availability propriety of the address information for each of the plurality of address information;
• the relay circuit relays the data by utilizing the address information set to be utilizable in the propriety information;
• the propriety information is set to “disable” when the data is not utilizable, and the propriety information is set to “enable” when the data is utilizable;
• and
• when a use frequency of the data is low or a use of the data causes a difficulty in a device, the propriety information of the data is set to “disable”.