CG-NATfrom English “Carrier-Grade Network Address Translation”, in Spanish “Large-scale network address translation”, is a technology that emerged at the beginning of this century and is regularly used by Internet operators to manage the shortage of IP addresses. available in the IPv4 protocol.
Using CG-Nat technology allows you to manage the assignment of public IP addresses while operators work on the transition to the IPv6 protocol, which will not have IP limitation problems. In the meantime, they use CG-Nat temporarily to more efficiently manage the limited resources of the IPv4 protocol.
How CG-NAT works
CG-NAT technology focuses on so-called “address translation”. Instead of each person having their own unique public IP address, all devices that are connected to the local network, for example the one you have right now at home, receive a private IP address.
Your Internet Service Provider then converts these private addresses into a shared public IP address when they communicate with the Internet.
This process allows operators to more efficiently manage the scarcity that IP addresses may have, which translates into less investment and greater operational ease.
This technology also greatly improves basic security. By not having a direct public IP, it is much more difficult for a remote attacker to directly access the devices you have connected to your network.
Limitations of CG-NAT technology
CG-NAT technology can have certain drawbacks, such as limitations when opening specific ports on your router to use certain applications, online games, FTP servers or NAS (network storage), and even certain home automation systems that require remote access.
Additionally, when sharing a public IP address with others, you cannot control incoming traffic or assign certain ports for certain tasks.
Having CG-NAT can mean an increase in latency in your connections and means that you may suffer blocks or even bans received by other users with whom you share the IP, something that could harm your access to certain services.
How to know if your Internet uses CG-NAT technology
If you want to know if you have CG-NAT on your Internet connection, it is recommended that you ask your Internet service provider.
If you have it active and you are not interested in continuing to use it, it is best to request deactivation, as long as your provider allows it. This may not be a free service.
On the other hand, to find out if your connection uses CG-NAT, you can try opening a specific port on your Wi-Fi router to use an app that needs it. If this is impossible, it is very likely that your connection uses this technology, which blocks ports from opening for incoming connections.
Finally, you could verify your public IP address by using websites that provide this information, such as What is my IP?
Compare the address that the page offers you with the IP that is reflected in your router configuration. If they are different, you may be under CG-NAT, because your router will show you a private IP on the screen while the public network is shared.
