How to Check If Your ISP Performs CGNAT

Do you suspect CGNAT is limiting port forwarding? If you are using an IPv4 address, this might be the case. Most ISPs (internet service providers) restrict port forwarding and access to specific platforms to prevent IPv4 exhaustion. 

This guide covers details on how to check whether or not your ISP performs CGNAT and how to bypass it.

What is CGNAT?

CGNAT (Carrier-Grade NAT) is a network technique used by ISPs  to conserve IPV4 addresses. Instead of assigning a unique IP address to each user, ISPs allocate temporary IP addresses from a shared pool, allowing multiple consumers to share the same IP. 

Pros of Using CGNAT for ISPs

1. Reduce Cost

CGNAT helps ISPs save on the high costs of acquiring additional IPv4 addresses, which reduces operational overhead.

2. Network Performance

CGNAT optimizes network traffic flow, enables ISPs to prioritize high-demand activities and enhance overall performance.

3. Customer Acquisition

CGNAT helps ISPs to accommodate a larger number of customers without exhausting their IP address pool. 

5 Major Downsides of CGNAT for Customers

1. Limited Connectivity

Sharing a single public IP address among multiple users under CGNAT complicates hosting services and establishing secure connections.

2. Reduced Performance

High bandwidth or low latency applications like online gaming and video conferencing may experience slower speeds.

3. Application Compatibility Issues

CGNAT can interfere with applications that rely on direct IP connections, such as VoIP, file sharing, and certain online games.

4. Port Forwarding Restrictions

Opening ports is not possible behind CGNAT, which is a common technique for hosting services or accessing remote devices.

5. Increased Risk of Blocking

Misbehavior by some users sharing the same CGNAT pool can lead to service disruptions or website blocks for others. CGNAT can impact the performance and reliability of various internet services.

3 Tested Ways to Check if Your ISP Performs CGNAT

There are several ways to determine if your ISP is using Carrier-Grade Network Address Translation (CGNAT):

Method 1: Check Your Router's WAN IP Address

1. Access your router's settings by entering its IP address (usually 192.168.0.1 or 192.168.1.1) into your web browser.  
2. Log in with your router's credentials.
3. Find the WAN IP address under the router's status or Network settings.  
4. If the IP address falls within the range of 100.64.0.1 to 100.127.255.254, it's likely your ISP is using CGNAT.  

Method 2: Compare WAN and Public IP Addresses

1. Follow steps 1-3 from Method 1 to obtain your WAN IP address.
2. Open a web browser and search for What is my IP address.
3. Note the public IP address displayed in the search results.
4. If the WAN IP and public IP addresses differ, your ISP is likely using CGNAT.  

Method 3: Traceroute Test

1. Open a command prompt on your computer.
2. Run the command "tracert your_public_ip_address" and press Enter.
3. If the traceroute shows only one hop, you likely have a direct public IP address.
4. If it shows two hops, your ISP is likely using CGNAT.

How Can I Open Ports Behind CGNAT On My Own?

There are various ways to access services behind CGNAT, including Cloudflare Tunnel, VPS, and static IP addresses from ISPs. A reliable VPN with port forwarding add-on and a dedicated IP can be your best bet to open ports behind CGNAT. A VPN allows you to have a unique public IP address by encrypting your internet traffic and routing it through a server with a public IP address, effectively bypassing CGNAT. 

How PureVPN Can Help You Open Ports Behind CGNAT

Forwarding ports on a home network being CGNAT is often blocked. While opting out is possible, it usually requires an expensive plan upgrade.

A more convenient and secure solution is to use a VPN. With PureVPN's port forwarding add-on and a dedicated IP, you can easily bypass CGNAT and forward ports to your device. Here’s what you need to do:

1. Get a PureVPN subscription with a dedicated IP and port forwarding add-on.
2. Login to the PureVPN member area.
3. Click the subscription tab.
4. Click Configure.
5. Apply your desired port settings.
6. Click Apply settings.

Can Your ISP Detect If You Are Using a VPN?

Yes, your ISP can see that you're connected to a VPN server. They can detect the time of your connection and the port used for VPN traffic. However, they can't see the specific websites you visit or the data you send and receive. By hiding your IP address, a VPN prevents your ISP from tracking your online activities.

Can I Host Servers while Using a VPN?

Yes, you can. CGNAT can limit your ability to host servers, as you need a static public IP address for others to connect to your server. PureVPN’s dedicated IP and port forwarding add-on gives you a unique IP address that isn't shared with other users, making it easier to host servers. Plus, you might need to open ports that are restricted due to CGNAT. ngs.

In Summary

Understanding CGNAT is essential for improving your online experience. Although it can help ISPs manage limited IP addresses, CGNAT can impact your online activities, if you rely on services like remote access, online gaming, or hosting servers. By using PureVPN, you can open ports, host gaming servers with a dedicated IP address, and experience unlimited internet access.