Tools CGNAT Detector

CGNAT Detector

Detect if your Internet Service Provider uses Carrier-Grade NAT. If you're behind CGNAT, port forwarding won't work - but there's a solution.

We'll analyze your public IP to check for CGNAT indicators. No data is stored.

Behind CGNAT? No problem.

portwarp tunnels bypass CGNAT completely - your game server gets a public address instantly.

Try portwarp - Free

What Is CGNAT?

CGNAT (Carrier-Grade NAT) is a technique used by ISPs to share a single public IP address among multiple customers. Your router gets a private IP from the ISP instead of a public one, which means you cannot receive incoming connections - even with port forwarding configured.

How to Know If You're Behind CGNAT

  • Your router's WAN IP starts with 100.64.x.x to 100.127.x.x (IANA reserved for CGNAT)
  • Your router's WAN IP is different from what whatismyip.com shows
  • Port forwarding is configured but ports remain closed
  • Your ISP only offers IPv6 connectivity

Solutions for CGNAT

  • Use a tunneling service - portwarp creates a public endpoint for your local server, bypassing CGNAT entirely
  • Request a public IP - some ISPs offer static public IPs for an additional fee
  • Switch ISPs - if possible, choose an ISP that provides dedicated public IPs