Net mask

Net mask | In conjunction with the IP address of a device, the netmask determines which IP addresses this device searches for in its own network and which it could reach via routers in other networks. It therefore separates the IP address into a network part (network prefix) and a device part. The network part must be the same for all devices in the respective network, while the device part must be different for each device within the network. The netmasks of all computers involved in an IP network should therefore be configured in the same way.