LTE / 5G Routers - Explaining Carrier Grade NAT

Remote Access & Port Forwarding doesn't work - Grade Carrier NAT?

Carrier-Grade NAT (CGNAT) is a networking technology used by internet service providers (ISPs) to conserve IPv4 addresses. As the world has exhausted the pool of available IPv4 addresses, ISPs have adopted CGNAT to enable multiple customers to share a single public IP address. This approach allows ISPs to serve a larger customer base without requiring a unique public IP address for each customer device. This means that these devices do not have a dedicated public IP address and instead share one with multiple customers.

In summary, Carrier-Grade NAT (CGNAT) is a technology employed by ISPs to share public IP addresses among multiple customers, leading to difficulties in accessing devices remotely from the WAN. By checking your WAN IP address and comparing it with a public IP lookup tool, you can determine if you have CGNAT. If you do, contacting your ISP to purchase a public IP address for your LTE/5G device will allow you to overcome this limitation and enable remote access.

Checking if you have Carrier-Grade NAT (CGNAT):

If you are experiencing difficulty accessing your LTE/5G device from outside the network (WAN), it might be due to CGNAT. To check if you have CGNAT, follow these steps:

1. Access the Web GUI Dashboard: First, log in to the Web GUI Dashboard of your LTE/5G router using the local IP address provided by your router manufacturer (e.g., "192.168.1.1")

2. Find the WAN IP: Once logged in, navigate to the section that displays the WAN IP address of your router. This information can usually be found under the Network or WAN settings
   

3. Check with a Public IP Lookup Tool: Visit a website that can show you the public IP address of your network. One such website is "https://whatsmyip.com". When you access this site, it will display your public IP address.
   

4. Compare the IPs: Compare the WAN IP displayed in the Web GUI Dashboard of your router with the public IP address shown on the "https://whatsmyip.com" website.

• If both IP addresses are the same, you do not have Carrier-Grade NAT, and you should be able to access your device from the WAN (outside).

• If the IP addresses are different, it indicates that your ISP is using Carrier-Grade NAT, and your device does not have a unique public IP address. As a result, remote access to your LTE/5G router from the WAN will not be possible.

• In the above example, we have a WAN IP of 10.204.58.202 and a public IP of 81.x.126.128 which means that we have a Grade Carrier NAT and we cannot access the device from the outside (from WAN)

Dealing with Carrier-Grade NAT:

If you discover that your LTE/5G device is behind a Carrier-Grade NAT and you need remote access, you must contact your ISP and request a public IP address for your SIM card or LTE/5G router. The ISP may offer this service for an additional fee, but it will provide you with a unique public IP address, enabling remote access to your device from the WAN.