A default gateway is a node that is present in the computer network that serves as a forwarding host to another network when the destination IP address of a packet does not match with any route.
The functions of default gateway are explained below −
The major function of the default gateway is to pass the information to another router when the current packet does not know the destination.
It is a node or a router in the network that connects the host to remote network components.
Whenever a packet needs to be transmitted to another network, the packet must pass through the default gateway and the default gateway identifies the destination route and forwards the packet on that route. It is considered as an exit point for the packets in the network.
You can find your PC’s default gateway IP address by following the steps given below −
By using the Command Prompt window, type “ipconfig” then press “Enter/Return” on your keyboard.
We can see a lot of information generated in this window.
Just scroll up and we can see “Default Gateway” with the device's IP address (e.g., 192.168.255.1) listed to the right of it.
When a default gateway is not configured on a host, the packet will be dropped. Packet won't leave the host at all. Default gateway should always be configured for the packet to reach the destination.
If default gateway is incorrectly configured, what situation may occur is explained below −
The host cannot communicate with other hosts in the local network.
The switch will not forward packets initiated by the host.
The host will have to use ARP to determine the correct address of the default gateway.
The host cannot communicate with hosts in other networks. A ping from the host to 188.8.131.52 would not be successful.
When a host needs to send a message to another host located on the same network it can forward the message directly.
When a host needs to send a message to a remote network, it must use the router also called as default gateway.
This is because the data link from the address of the remote destination on the host cannot be used directly.
Instead the IP packet has to be sent to the router and the router will forward the packet towards its destination.