ip.uk.app Get yourname.uk.app

Am I behind CGNAT?

Find out whether your broadband gives you a real public IPv4 address, which you need for port forwarding and hosting a server at home.

The internet sees you as 216.73.216.141. Enter the IP address your router reports as its WAN or internet address.

How to find your router’s WAN address

  1. Open your router’s admin page, usually 192.168.1.1 or 192.168.0.1. On BT Smart Hubs it is 192.168.1.254.
  2. Look for Status, Internet, Broadband or WAN.
  3. Copy the IPv4 address shown there. It is not the router’s own 192.168.x.x address.

Reading the result

Frequently asked questions

What is CGNAT?

Carrier‑grade NAT means your ISP shares one public IPv4 address between many customers. Your router gets a private address from the 100.64.0.0/10 range, or similar, instead of a public one.

Which UK providers use CGNAT?

Many alternative fibre networks and most mobile and 4G/5G home broadband services use it. Several providers will give you a public IPv4 address on request, sometimes for a small fee.

Can I run a home server behind CGNAT?

Not with ordinary port forwarding over IPv4. Your options are to ask your ISP for a public IPv4 address, use IPv6 if your provider supports it, or use a tunnel such as Cloudflare Tunnel, Tailscale Funnel or a small VPS.

Is a double NAT the same thing?

Not quite. Double NAT means two routers at home, for example an ISP hub plus your own router. You can fix it yourself with modem mode or by forwarding ports on both. CGNAT happens at your ISP, outside your control.