What is Carrier-grade NAT (CGNAT)?

With the IPv4 pool depleting every day, we are at the end of an era. Initially deployed in 1983, the protocol was used to connect devices on the internet. These connections heavily relied upon an IP address of 4 octets. But as the world is transitioning towards the IPv6 protocol, we need a method to extend the IPv4 pool.

That is where CGNAT comes in! With these network address translation gateways, ISPs can effectively use the IPv4 infrastructure without added costs. 

Want to learn how? This comprehensive guide will walk you through the basic ideas behind CGNAT.

CGNAT – a backdrop

Around 41 years ago, when IPv4 was first introduced, the 4,294,967,296 IP addresses were considered sufficient. However, the thought did not last long. The pool of IPv4 addresses continues to lessen by the day and force ISPs to invest more in acquiring new IP addresses for users. The new IP addresses are costly due to their rising demand and decreasing availability. 

On the other hand, ISPs started performing CGNAT to continue providing services to their customers. With CGNAT, the ISPs can assign the same IP address to multiple users and don’t have to buy a unique IP for every user, and save up costs on their IPv4 structure.

Here is a more in-depth analysis of CGNAT, its purpose, and its effects on your internet experience.

What is CGNAT?

CGNAT is a network address translation technique that extends the IPv4 networks on a considerable scale and allows ISPs (internet service providers) to conserve their acquired IPv4 pool. 

Every online user has two IP addresses, a public and a private one. When a user intends to communicate online, the standard NAT protocol translates their private IPv4 address to a public one. 

But with CGNAT (LSN or NAT 444), an extra layer of address translation is added. The unique private IP addresses are translated into public IPs shared by multiple users. And this is how ISPs prevent their IPv4 pool from exhaustion.

How do I know if my router is behind CGNAT?

While CGNAT is highly beneficial for ISPs, it can provide certain limitations for users. There are a couple of strategies in place for this query.

Compare your router’s WAN IP to the publicly attained IP address

One of the simplest methods is the use of the WAN IP Address. You need to compare your public IP address with this WAN IP simply. If the public address is the same as the WAN IP, then rest assured that you are not behind CGNAT.

But if that is not the case, then your ISP is using CGNAT to conserve IPv4 addresses. Here is how the process goes:

1. Open up a web browser.
2. Type What is my IP in the URL bar.
3. Hit enter.
4. The browser will display your public IP address on top of the screen.
5. Note down this IP address.
6. Now log into your router’s settings by typing in the router IP in the URL.
7. Use your username and password to log in.
8. Navigate to the Status page.
9. Here you can check the ISP-assigned WAN IP address.
10. If both IP addresses are the same, then you are not on CGNAT.
11. However, if this WAN IP differs from the public IP address, you are behind CGNAT.

Traceroute to your public IP

This method  mainly uses the command prompt. In this method, you must count the number of hops in the trace. Don’t know how that works? Here is a detailed overview of the steps:

1. Open up a web browser.
2. Type What is my IP in the URL bar.
3. Hit enter.
4. The browser will display your public IP address on top of the screen.
5. Note down this IP address.
6. Now open up the command prompt by pressing the windows key and typing cmd.
7. In the prompt window, type tracert (put in your public IP).
8. Hit Enter.
9. If the trace shows a single hop, you are not behind CGNAT.
10. But if the trace shows two hops, your ISP uses CGNAT.

Does CGNAT affect gaming?

CGNAT can cause problems with port forwarding. Many online games require you to forward ports to maintain a stable connection. With CGNAT, Port Forwarding becomes a lot more complicated as the public IP address is shared by multiple users. 

What is the CGNAT IP address?

As mentioned above, your ISP assigns a public IP address to multiple users. This IP can be termed a CGNAT IP address and generally belongs to the range of 100. x.y.z addresses. 

If your current IP address lies in the said range, there may be a possibility that your internet service provider is using CGNAT to conserve IPv4 addresses.

Can you bypass CGNAT?

You can stick with CGNAT, and it would not pose any issues unless you want to forward ports for better connectivity. Since many games and applications require Port Forwarding, you may have to remove or disable CGNAT. 

But is that even possible? Of course, it is! Removing CGNAT or opting out is an option that is offered by some ISPs. You can contact your ISP or the technical support line and state a valid reason to opt-out of CGNAT. This will result in your public IP address changing. But if you have a static IP address, you do not need to worry as the said IP is not affected by CGNAT. 

Quickly and safely bypass CGNAT using PureVPN

Opening a port shouldn’t be complicated. With the Port Forwarding add-on, it’s as simple as 1, 2, and 3!

How do I bypass CGNAT?

While it may be an option to opt out of the CGNAT plan, you can bypass all the issues related to CGNAT without having to go through technical support. How? Just use a reliable Port Forwarding VPN service.

You can use the PureVPN port forwarding add-on to make this process easier. This add-on will bypass CGNAT and allow you to set up port forwarding for your devices. Here’s how:

1. Login to the PureVPN member area.
2. Click the subscription tab.
3. Click Configure.
4. Apply your desired port settings.
5. Click Apply settings.

Wrapping up

And that’s that. This blog has covered almost everything you would want to know about CGNAT. While CGNAT can be a source of relief for the ISPs, it can also setback your network connections. But you can always bypass these restrictions with a reliable VPN service!