Default gateway

A default gateway is the node in a computer network using the Internet protocol suite that serves as the forwarding host (router) to other networks when no other route specification matches the destination IP address of a packet.

The networking software stack of each computer contains a routing table that specifies which interface is used for transmission and which router on the network is responsible for forwarding to a specific set of addresses.

If none of these forwarding rules is appropriate for a given destination address, the default gateway is chosen as the router of last resort.

A device wishing to communicate with a host on the public Internet, for example, forwards the packet to the default gateway for its network segment.

The following example shows IP addresses that might be used with an office network that consists of six hosts plus a router.