What Is a Network Gateway?

How is a gateway different from a router?

A gateway connects networks, while a router typically delivers data within a network. Historically, gateways and routers have been separate devices. However, it’s becoming more common for their functions to be combined and simply called a router. For example, the Wi-Fi routers commonly provided for home and small business internet service are both a router (delivering data) and a gateway (translating it so destination devices can use it).

How does a network gateway work?

A physical network gateway includes network interface cards (NICs) and inputs and outputs—usually Ethernet—and software for translating network protocols. Gateway functions may also be defined, deployed, and controlled through software, and are increasingly being built into routers and other equipment.

A gateway is typically used on the network layer of the Open Systems Interconnection (OSI) model, but it could theoretically be deployed on any of the OSI layers. Standalone or virtual gateways may be placed anywhere in a network where translation is needed. They can be unidirectional (allowing data to flow in only one direction) or bidirectional (allowing data to flow both in and out of a network).

As an entry or exit point for data, a gateway can be used in a variety of security processes, such as a firewall to scan and filter data or a proxy server to maintain restricted access to certain applications or assets.