All definitions of a gateway (that I can find) suggest it is a device (or software) that translates protocols between networks.
Routers know where IP addresses are (or where to go to if they don't) that the LAN (or a request from a LAN) do not know how to get to.
If we had two TCP/IP networks, say one on the 7th floor and one on the 8th floor of a building, that need to communicate at times to one another (no hubs or switches allowed), would the device that connects the two networks be a router or a gateway?
My argument is that a router can redirect the request from one network to the other network and, therefore, a gateway is not required since no protocol change is necessary.
A big part of my confusion is that when setting up the IP on a node computer, the box that the non-LAN IP address goes in is labeled "Gateway" (Start --> Control Panel --> network connections --> local area network --> support --> "default gateway").
But why is the device in the middle of the two networks in the above scenario considered a gateway when there is no protocol translation?
Please tell me I'm right so I can rub it in, or tell me I'm wrong so I can accept my humiliation sooner rather than later. Thanks.
The reality of the above terms is that they are both interchangeable and either are used when routing data between two or more networks, regardless if the protocols they are using are similar or not.
In a local network, the gateway is the door out of the network. The gateway will also "route" packets between your network and whatever is on the other side; hence, your gateway is also your router -- and vice versa.
This was first published in April 2005