What Is Gateway?

A gateway is like a border guard of your network. It's the gatekeeper for all of your data, and it makes sure that anything coming in or going out is safe to do so. Suppose you've been abroad and had to go through customs before boarding a plane. In that case, you'll be familiar with this concept: they check everything you have with you—your suitcase, the contents of your pockets—to ensure you're not bringing anything dangerous into the country. That's what a gateway does for your network: it checks incoming data to ensure safety. A gateway device can also check outgoing data, ensuring it's encrypted before sending it off into the wild blue yonder. The most common network gateway device is a router (or "layer three switches"), which sits between two separate networks and routes traffic between them according to its configuration rules. Gateways are often used when connecting remote networks or autonomous systems because the remote nodes don't have access to other routers on their side of things (which would allow them access to other networks). A gateway is just like a door to the internet. It's an intermediary between your network and other networks and routes all traffic between them. It's like this: when you want to send someone a message on the other side of town, you don't just throw it over your shoulder and hope it gets delivered—you put it in a box and mail it. The mailbox does much work for you, including picking up mail from all the other people in town. That's what gateways do! They collect packets from different networks and deliver them to their destinations. Gateways track which network nodes communicate with each other so they know where to send your packages. If multiple paths are available between two networks, gateways can use that information to pick the fastest route for data transmission.