Double NAT is something that you almost always want to avoid on your home network. If you are getting a double NAT detected error on Xbox Series X, you are going to have trouble with multiplayer gaming, using features such as voice chat, and using other internet connected features.
Generally, in most cases, the solution to eliminating your double NAT issues is not that complicated. Most gamers should not have any trouble fixing a NAT error. However, there is a lot of misinformation on the internet regarding double NAT and how to fix it. You can’t fix NAT error issues simply by changing settings on your Xbox Series X or Xbox Series S.
Double NAT is a very specific issue that has a very specific cause. Here is a step-by-step tutorial on how to fix double NAT issues on Xbox permanently.
Table of Contents
What Causes Double NAT
Double NAT occurs when you have two or more routers connected to each other and improperly configured. In many cases, this is because you have your own router plugged into a router provided by your internet service provider (ISP). It can also happen when someone decides to add a second router for either more WiFi coverage or for additional ethernet ports and doesn’t configure things properly.
You only want a single router on your home network. If you are using your own router, you do not want to also have routing enabled on your ISP’s gateway device. Having two or more routers connected together, both performing NAT, is what causes double NAT.
Double NAT is not conducive to online gaming as it makes connections originating from outside your network get dropped. Many online games use P2P connections that simply do not work behind two layers of NAT.
|Examples of Single NAT Setups||Examples of Double NAT Setups||How to Fix the Double NAT Issue|
|ISP Gateway — Xbox||ISP Gateway — Customer owned router — Xbox||Eliminate the customer router or enable bridge mode|
|ISP Gateway — Network Switch —Xbox||ISP Modem — Customer Router 1 — Customer router 2 —Xbox||Eliminate on of the customer routers|
|ISP Gateway in bridge mode — Customer-owned router — Xbox||ISP Gateway — Customer router — Network Switch — Xbox||Eliminate the customer owned router or enable bridge mode|
|ISP Modem — Customer owned router — Xbox||ISP Modem — Customer Router 1 — Customer router 2 —WiFi Access Point — Xbox||Eliminate on of the customer routers.|
How to Fix Double NAT
Double NAT can generally be solved quickly and easily with just a few simple steps. With most residential ISPs getting a properly configured setup with a single layer of NAT is straightforward.
- Determine how many routers are on your network.
- Check to see if your ISP has given you a modem router combo, AKA a gateway or a straight modem.
- Remove any routers from the signal chain after the first router.
- Put your ISP gateway into “Bridge Mode”, if you have a straight-up modem, skip this step entirely.
- Test your Xbox Series X and verify you are no longer getting a double NAT detected error message.
Identify Any Routers or Gateways on Your Home Network
The best way to do a quick search for any routers or gateways on your home network is to start from the end and work backward. This is consistent with the CompTIA best practices for IT troubleshooting.
In this case, start with your Microsoft Xbox Series X or Xbox Series S console. Then trace the ethernet cable back to what it plugs directly into. Note if that is a router or simply an ethernet switch.
If your Xbox is connected wirelessly, trace the origin of the WiFi signal to where it is being broadcast from. Determine if that device is a router or simply a wireless access point.
Continue this process of working backward until you reach the demarcation point (DEMARC) for your building. The DEMARC is often a locked box installed by your ISP either on the outside of your residence or in a basement or utility room.
At this point, you will want to count up the number of routers that are connected between your Xbox Series X and your DEMARC point.
Check if Your ISP Modem is Also a Router
By default, many residential ISPs will give you a device called an internet gateway. An internet gateway provides the functionality of a modem and the functionality of a router in a single box. A gateway in its default configuration is going to perform NAT.
If you have a straight-up modem from your ISP, it does not include router functionality and therefore does not do NAT. Unlike a gateway, a modem is not a NAT device.
Once you have determined whether you have a modem or a gateway from your ISP, you can move to the next step.
Remove Any and All Routers Except the First Router
Now that you have determined that you have multiple routers on your network, it is time to fix that. You only want a single router running on your network. Having additional routers means having additional layers of NAT running. This is where double NAT issues stem from.
If, when removing routers, you find that you need more ethernet ports, replace your routers with simple ethernet switches. They can be purchased for as little as $15 online, and you can get switches with as few ports as 5 or as many as 48.
Technically you could reconfigure your router to act as a switch to avoid needing to purchase one. However, given how inexpensive switches are and the fact that many routers have lower-quality switches in them, I would personally recommend avoiding this option at all costs.
Put Your ISP Gateway into Bridge Mode or Get a Straight Modem
If you determined that your internet service provider is using a gateway rather than a plain modem, you would need to enable bridge mode on it. Putting your gateway in bridge mode will make it act as a plain modem and pass your public IP address along to your own router.
This is what you want to happen. When your router is getting a public IP address from your ISP, you will avoid double NAT.
If your ISP gateway is not in bridge mode, you will have NAT running on your ISP gateway and NAT running on your own router. This is double NAT. Enable bridge mode on your ISP gateway to fix this issue.
Another option would be to replace your ISP gateway with a straight-up modem. Many but not all residential ISPs will allow you to use your own modem instead of the gateway they provide by default. This has a few advantages.
- You can get a straight modem without router functionality
- You can get a better quality unit than what your ISP provides you with
- You can avoid paying a monthly modem rental fee of usually between $5 – $15
Test Your Internet Connection on Your Xbox Series X | S Console
Restart your Xbox console and open up the network settings menu. Then test your internet connection. Assuming that you eliminated all of the routers after the first from your network, you should no longer see the double NAT detected error message on your Xbox Series X.
If you are still getting the error message, look once again for any routers that you might have missed. This is by far the most likely reason for your double NAT issue.
However, there is one other less common scenario that could be the source of your trouble. This is if your ISP uses carrier-grade NAT (CGNAT).
Does My ISP Use CGNAT
The vast majority of internet service providers do not use CGNAT technology for fixed residential internet connections. AT&T Fiber, Verizon Fios, Xfinity, Spectrum, Breezeline, Fidium Fiber, Centurylink, and Cox are all examples of internet providers that provide residential customers with publicly routable IP addresses rather than using CGNAT.
CGNAT is primarily used by cell phone carriers on their 4G and 5G networks. This means that some cellular-based home internet services, including T-Mobile Home Internet and Verizon 5G Home internet, use CGNAT to provide customers with a private IP address.
You are also going to have issues with CGNAT if you are using a mobile hotspot.
Many satellite ISPs, including Starlink, HughesNet, and Viasat, all use CGNAT for their residential internet plans. Fewer cable, DSL, and Fiber-based ISPs use CGNAT for residential customers. However, with the scarcity of IPv4 addresses and the slow rollout of IPv6, many newer ISPs, especially in developing countries, are opting to use CGNAT.
Why Does CGNAT Matter for Xbox Live
CGNAT is an issue for online gaming. This is because when your ISP uses CGNAT on their network, you are behind double NAT, no matter what you do. With CGNAT, your internet provider is running NAT on their side before the signal even reaches your home.
This means that when you add your router as required by your ISP, you now have two layers of NAT. This is double NAT, and it is outside of your control.
If you have an ISP that uses CGNAT, you may have a hard time gaming on Xbox Live, and your NAT type will likely be strict.
The best solution in this situation is to find an ISP that doesn’t use CGNAT or allows you to get a public IP added to your account.
The public IP doesn’t have to be static, it can be dynamic. Either way is fine. What matters is that your IP is publicly routable.
In most areas, there are one or more internet providers that offer a public routable IP. If you are unable to switch ISPs, there is one other option.
A VPN that offers a static IP address can also be used to bypass CGNAT limitations. This is not an ideal solution, especially for gaming. However, it can be used successfully and is a good option if you must live with using an ISP that uses CGNAT.
What is NAT on a Home Network
NAT stands for network address translation. NAT is a normal function used on home network routers. It is essential for connecting multiple devices to a single residential internet connection.
NAT works by creating a private network that your devices can all connect to that is able to share the single public IP address provided by your internet service provider (ISP).
Network address translation is not a bad thing, and most internet activities are not impacted by NAT whatsoever. Gaming and other P2P applications can be impacted. Fortunately, game designers have designed games to work through the limitations of NAT.
The problem is with double NAT. Game developers have a much more difficult time designing games to be able to cope with having two layers of network address translation to traverse.
Conclusion: Double NAT Detected Error
Getting a double NAT error message on Xbox is not uncommon. Fortunately, it is a relatively easy thing to remedy. As an added bonus, fixing your double NAT will improve the performance of other devices on your network as well as your Xbox Series X.
Double NAT is just a poor network configuration. Eliminating it is a best practice. As an IT systems administrator, I can tell you all too well the number of issues double NAT can lead to. Fix it once, make it right, and forget about having issues related to double NAT.