A default gateway in a computer network is the device that serves as the routing node that a computer uses to send information to a computer in another subnet or the internet. It’s typically a router or networking device that a networked computer uses to send out data to destinations outside its own network when no better route is specified in the routing table. The default gateway forwards traffic from the local subnet to devices on other subnets, providing a routing path for the data to follow.
When configuring a device’s IP address, subnet mask, and other network settings, the default gateway’s IP address must be specified so that the device knows where to send traffic intended for outside of the local network. If a data packet’s destination is not on the same local network, it is forwarded to the default gateway for the next step in its journey to the destination.
In an IPv4 network using the 192.168.0.0 address space, the IP address 192.168.0.1 is often used as the default gateway and therefore cannot be used as an IP address for any other device. Sometimes 192.168.0.254 is used, but is not standard.