Am I behind CGNAT?
Two numbers decide it: the WAN IP your router has, and the public IP the internet sees. If they match, you have a public IP. If they don't, there's NAT between you and the internet, usually CGNAT.
Step 1: Your public IP (what the internet sees)
Click the button to look up your public IP. Your browser asks this site's own server twice, once over IPv4 (v4.cgnat.wtf) and once over IPv6 (v6.cgnat.wtf). It also shows which network (ISP) you're on. The IP check runs only when you click and uses no other service, and this site stores and logs none of the results.
- Public IPv4
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- Public IPv6
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Step 2: Your router's WAN IP
Log in to your router or gateway (often 192.168.0.1, 192.168.1.1 or 10.0.0.1, or the ISP's app) and find WAN IP, Internet IP or IPv4 address on the status page. Ignore the LAN/local address.
How to read the result
| WAN IP is in 100.64.0.0 – 100.127.255.255 | CGNAT This range (100.64.0.0/10) is reserved for carrier-grade NAT (RFC 6598). Inbound port forwarding over IPv4 won't work. |
|---|---|
| WAN IP is 10.x, 172.16–31.x or 192.168.x | NAT upstream Something in front of your router is doing NAT. It's either your ISP's gateway (double NAT, often fixable with bridge or passthrough mode) or the ISP itself. |
| WAN IP equals your public IPv4 | Public IP No CGNAT. Port forwarding can work, subject to your ISP's terms and any port blocks. |
| WAN IP is public but different from your public IPv4 | Check again Your IP may have just changed, or traffic leaves through a different address. Re-check, and make sure you're not on a VPN or proxy while testing. |
IPv6 isn't affected by CGNAT. If you have a public IPv6 address (usually starting with 2 or 3), devices may be reachable over IPv6 from IPv6-capable networks, if your router's firewall allows it.