Default Gateway IP Address vs. Router IP Address
If you’ve ever setup a router before, you may have seen a setting called “Gateway IP address” that appears either before and/or after setup. But you might be wondering: is the Gateway IP the same as the router’s IP address, or is it something different?
The answer? It depends, but they are usually the same.
The “default gateway” is simply the IP of the next hop for traffic that is not explicitly routed anywhere else. This will, almost certainly, be an IP address on an interface of a local router. However, it may not be an address on which you can manage the router.
If this is for a “home-type network”, the inside IP (your default gateway) and the management address will probably be one and the same, but in a “large/corporate-type network” I wouldn’t be so sure.
What is a network gateway anyways?
Without going into too much detail, the “default gateway” in terms of networking jargon is usually the very first “hop” that occurs between a local computer (or other device) and it’s local network hardware. For home users, that is almost certainly going to be a hardcoded IP address chosen by your router’s manufacturer; for example, 192.168.1.1 is the most common IP address for consumer gateway hardware.
| Gateway | Router | |
|---|---|---|
| Purpose of IP address | serves as the first hop between local devices and the network | mainly used for sysadmins to login and manage settings |
| Purpose of hardware | translates protocols and connects one network to another network | delivers the actual data to various devices on a network |
In fact, one of the oldest router manufacturers, Cisco, reminds us that gateways actually used to be separate hardware from routers, and only after designs became more integrated did the confusion arise between “gateway IP” and whatever IP address the router provides for management access.
The gateway’s job is simply to “translate” one protocol to another. It’s the router’s job to actually transport the data. But by combining modern network gateways into the router itself, it made things easier to manage — they can even share an IP address!
Modern routers also have gateways
So now you can understand better why that router you bought for your home or office has this “default gateway” setting. It’s because, over time, networking equipment manufacturers began combining the network gateways into the routers to make things easier (and cheaper).
If you are one of the 99% of people who have a typical “consumer grade” router, then this applies to you, and that means there’s a very strong chance your router’s “login” IP address (for management) is exactly the same as the “default gateway” IP address.
In academic terms, a gateway is a network middle box that works at any layer from 1-7 of the 7-layer OSI model for describing networking protocols, whereas a router only works at layer 3, the Network layer. Most home gateway products, such as those we call “wireless routers” in layman’s terms, are actually NAPT gateways, not just layer 3 routers. Some of them can be configured to act as simple layer 3 routers in some cases, but most of the time they act as NAPT gateways.
For the small number of networking geeks who have a complex setup, mostly at a large company or organization, they might have a separate Layer 3 “gateway” apart from their router. But this approach simply doesn’t apply to most people or situations, and thus, what is commonly called a “router” these days is actually a router and a gateway combined, both in the Layer 3 of the OSI networking model.