What is a Double NAT?
NAT is short for Network Address Translation. This is how your router translates the public IP (the entire network provided by your Internet service provider) to the private IP address of your computer and home network. The router is responsible for NAT.
When you add a second router to the network, you create a second NAT. In many cases, duplicate NAT does not cause any problems, but it makes port forwarding almost impossible and can cause universal plug and play problems.
That said, if it does create problems with your network, there are a few steps you can take.
Remove the ISP Router From Your Network
The simplest solution to correcting a duplicate NAT is to get rid of one of the routers that is causing the problem. If you have connected two routers but don’t really need one, just use the router provided by your ISP.
However, if you are an energy consumer, this solution is probably not the best option for you. The routers provided by the ISP don’t have the features that the more expensive options have. In this case, you can remove your ISP router from the network.
Connect the network cable from your modem to the WAN port on your personal router. Once you have connected the network, you need to log into your router’s setup menu and configure it.
How to Configure Your Router
Login to your router through a browser by entering your router’s IP address in the URL bar. Most routers use 192.168.1.1 as their default IP, but this will vary. If you are not sure, you will need to find out the IP address of your router.
Go to your PC’s command line terminal by typing Run cmd. Once the terminal appears, enter ipconfig. On the screen that appears, scroll down until you find the default gateway. The number next to it is the IP address of your router.
Once you’ve found the address, you’ll need to log in with your router’s username and password. This is usually at the bottom of the device, but you can change the username and password if necessary.
After logging in, you need to change various settings. However, these settings differ by router and ISP. If you are not sure how to proceed, contact your ISP for assistance or check their website; Most service providers have detailed information available to users online.
Enable Bridge Mode on Your Router
Another solution to the double NAT problem can be found in the bridge mode settings on your router. Bridge mode disables the NAT function of the router and allows it to act as a server without an IP address conflict; in other words, it transmits the original router settings.
In some cases, you will not have access to it, especially if you are using a router provided by an ISP. You need to call your ISP and request that your router be put into bridge mode. However, if you can configure the settings on your router, it’s an easy move.
Log into your router using your browser to access the configuration settings. After logging in, look for the option to enable bridge mode. This is in a different location depending on your router, but sometimes just clicking “Enable” is sufficient. Of course, sometimes it is more difficult to configure the router after you have enabled it.
How to Fix Double NAT on Xbox
One place where double NAT is a problem is in games. For example, many Xbox One users have received an error message stating that a duplicate NAT was detected on their network.
In games, you want Open NAT or Nat Type 1. This allows for the widest possible compatibility and allows you to participate in any game or session. If you have moderate NAT or Nat Type 2, you can connect to most sessions, but it has limited functionality.
NAT Type 3 or strict NAT is the problem. This makes it almost impossible to join someone in the game. Sure, single player games are still an option, but trying to play an online game will be fraught with difficulties.
Double NAT creates problems when trying to play in a multiplayer mode and can even cause your Xbox to connect to the internet. If you get this error, you need to fix the problem by removing one of the routers or by enabling bridge mode as shown above.
Another solution is to connect the Xbox directly to your router using an Ethernet cable. In most cases, this will eliminate the double NAT problem; just use the first router on your network, not the second, as a connection point.
All of these solutions can correct a double NAT error. In most cases, you don’t need a second router on your network. If your original router is not strong enough to carry the network throughout your home, you can use a replacement router as a WiFi extender.