What is NAT on your router?

Wondering what those pesky NAT warnings are about? It's a little complicated.

Open NAT setting in the ASUS Router app for the ROG Rapture GT-AXE16000

The only time most of us think about NAT is when it’s a problem. If you’re a gamer, there’s a chance you’ve seen the dreaded double NAT warning or have been informed that your strict NAT type could cause issues. A strict NAT type can also make it more difficult to connect to a specific device from an external network. In gaming, this usually manifests as longer than ordinary matchmaking times or the inability to hear others in voice chat.

What is NAT?

NAT stands for network address translation and in its most basic form, it translates an external IP address to an internal one. This is because each device that’s connected to the internet needs to have an IP address to send and receive information. The problem is that there are simply not enough IPv4 addresses, with around 4 billion available, to assign a unique one to every device in the world. As a result, a home router will assign an internal IP address to each device connected to it and translate that to an external IP as needed. It's like finding an office in a large building — a GPS app will get you to the front door, but you'll need to find a directory inside to get exactly where you need to go.

While IPv6 exists and does have the capacity to give each device an individual address, the internet at large is still operating with a mixture of IPv4 and IPv6, meaning that NAT is still needed. While it would be nice to flip a switch and move everything over to IPv6, that’s simply not realistic. A lot of hardware needs to be replaced to keep it all working and ISPs, especially smaller local ISPs, might not have the cash on hand (or motivation) to pull this off.

NAT isn’t a one-size-fits-all solution, however, and there are multiple types you may encounter. The first is Type 1, also known as Open, which allows your device to connect directly to the internet as if it's not connected to a router. This is often preferred by some gamers, as it allows your device to connect to just about any other player.

Next is Type 2, or Moderate, which allows you to connect to both Type 1 and Type 2 players. If you’re using a router, which most of us are, you’ll likely see Type 2 NAT with default settings. For the most part, NAT Type 2 should be perfectly fine for gaming.

Type 3, or Strict NAT, will cause the most issues since it only allows for connections to Open connections. If you’re trying to play online games with a Strict NAT, you’ll likely experience long matchmaking times, if it connects at all. You may also experience issues using services like voice chat. This usually means you’re connected to a large internal network such as in an office building, and you’ll need to talk to your network admin to see if you can get a port out.

What can I change on my router?

If your router is connected to the internet through another router, such as the one provided by your ISP, you could encounter an issue called double NAT. This is where two devices are trying to handle NAT and conflicting with each other. To avoid this, you can set your router to bridge mode instead of router mode. This is often found in a section labeled as WAN, Internet, or similar in your router's settings. Most of the best routers, even basic mesh systems allow you to change this setting. This allows the router closest to the internet connection, such as the box provided by your ISP, to handle NAT.

You could also add a rule to create an exception for a certain connection. If you want to alleviate NAT issues for a specific connection, such as a game, you can use port forwarding. Some routers, such as gaming routers, make this a lot easier by providing a list of games and their required ports to allow you to configure them with just a few clicks. If your settings are a bit more basic, you can find the port needed for your games specifically and add a rule.

NAT type settings on an ASUS ROG router

You may also find the option to choose between Full Cone and Symmetrical for your NAT type. Full Cone maps all connections from an internal IP address to the same external IP address and port. Symmetrical only maps connections to the same external IP address when connecting to a specific destination IP. ASUS, on its ROG routers, recommends Full Cone for the best possible gaming connection. There are several other ways NAT can be referenced, so if your router’s terminology doesn’t specifically match these, you may need to check your documentation to find an equivalent setting.

Before jumping into your router’s advanced settings and changing settings, it’s worth considering if you even need to. Opening ports and switching to more open NAT settings can reduce security with more points of entry to your network. It may be tempting to start adding new rules for all of your favorite games, but the fact of the matter is that many of them will work without issue at default settings. Finally, some users getting strict NAT on their home connection report that a simple router restart can resolve the issue. You should really only be messing with NAT settings if you’re having consistent issues connecting.

If you’re a gamer looking for the best possible gaming connection, you’ll be better served by enabling QoS for your gaming device to keep latency down. QoS prioritizes specific connections to keep pings as low as possible when you’re sharing your networks with others. That being said, opening ports on a restricted connection can open you to a larger pool of players to improve your odds of getting into a game with other players with better pings, but many games and systems will work absolutely fine with Type 2 NAT.