The appearance of double NAT when using two routers is a problem when accessing certain services or even if we want to play online. You may be suffering from this problem and you were not even aware of it, so we are going to tell you why it happens and how to solve it.
In most cases, double network address translation, also called double NAT, does not affect Wi-Fi network performance. However, it can be a problem if you play online or use port forwarding and Universal Plug and Play (UPnP) rules.
What is double NAT?
Having double NAT is common if two routers are installed on the same network. This means that the problem appears when two routers are interconnected with each other , causing two translation tables to exist. On the one hand, we will have the router provided by your Internet provider, which connects directly to the network, and, on the other, a second router to expand Wi-Fi coverage or with specifications for gaming and improve the quality of the game.
Double NAT
In addition to this duplication of routers at home, double NAT usually occurs in large networks, such as student residences, schools and offices, because they use a main router and other secondary ones so that the WiFi signal covers the entire space that your building has. .
The problem is that, sometimes, those two routers end up having conflicts with each other. Being connected to a secondary router, the public IP is not managed by that equipment, but by the main router. If the IP cannot be seen by the servers of any of the games you are going to play, this is a problem because the servers need the IP addresses so that the data exchanged has a destination point.
Being connected to a second router that is not the one originally installed by the provider, that router will create a packet with the original address and the private IP that the DHCP of the first has assigned to it. In turn, in the second hop (to the operator’s router), the packet is modified again, changing the address of the packet and setting the private router and the real public IP. Once it has been processed in the corresponding server, this packet will return and generate some confusion between the routers .
You can check if you are using double NAT with a tracing route (tracert report). Once the trace path is complete, check the first two IP addresses listed. If they are both private IP addresses , you are using double NAT.
Private IP addresses typically appear in these number ranges:
- 10.0.0.0 to 10.255.255.255
- 172.16.0.0 to 172.31.255.255
- 192.168.0.0 to 192.168.255.255
How to fix double NAT?
The simplest solution is to connect our gaming console or PC directly to the main router via Ethernet. Thus, we should configure the secondary router in bridge mode or, failing that, try to change the router so that it works only as an access point. This will remove it as NAT from the network. Bridge mode disables the router’s NAT function and allows it to act as a server without an IP address conflict; in other words, it broadcasts the initial router configuration.
Another possible solution is to assign a static IP to the affected console or device and manually open the ports it needs to function properly. Finally, you should activate the UPnP function of the main router , since it serves to facilitate the connection between said router and the secondary or specific one for gaming and thus avoid duplication of NAT.