Understanding CGNAT: Why You Might Not Truly 'Own' Your IPv4 Address

Introduction: The Ultimate Roommate Situation

Because the world has run out of IPv4 addresses, ISPs have a problem. They have millions of new mobile phones and smart homes, but no new IP addresses to give them. Their solution is Carrier-Grade NAT (CGNAT). Instead of giving your house a public IP address, they give your neighborhood a public IP address, and your house just gets a 'private' extension number.

The Double NAT Problem

It’s like living in a massive apartment building where everyone shares one mailbox. For normal web browsing, this is fine. But if you want to host a multiplayer game server or access your security cameras from work, CGNAT breaks everything. 'Port Forwarding' is impossible because you don't even own the public 'Door'.

Conclusion

CGNAT is a necessary evil to keep the internet running during the slow transition to IPv6. If your internet feels restrictive, this is likely why. Check if you are trapped behind CGNAT here.