When I talked about IP addresses, I mentioned default gateways, but didn't go into any details about them at the time. The default gateway is one of the three basic network interface configuration elements of IP networking along with the IP address and the subnet mask. A default gateway is usually, but not always necessary to have a working IP network configuration. As I stated last time, you might know you need to configure a default gateway, but not why.

The default gateway is a host, identified by its IP address, on the local network to which you send packets when the destination address is not on the local network. The default gateway will then, hopefully, forward the packets toward the destination network. But what does all that mean?