Focused home-network toolkit
Find why inbound connections, hosting, or port forwarding are failing
Use a tightly focused toolkit for CGNAT, NAT type, double NAT, bridge mode, WAN IP mismatches, and public port reachability. Everything here is built around one problem: why your home network cannot accept inbound connections.
Core tools
One focused troubleshooting toolkit
Tool
CGNAT Checker
Compare your router WAN IP with your detected public IP and look for strong signs of CGNAT.
Open toolTool
Port Checker
Test whether a TCP port appears reachable from the public internet and see the next troubleshooting steps.
Open toolTool
NAT Type Check
Understand open, moderate, and strict NAT in plain English and see what to check next.
Open toolSupport guides
Build the full picture before you change more settings
Guide
Why port forwarding fails
Work through the most common reasons inbound connections stay closed.
Read moreGuide
Learn what CGNAT means
Understand why ISPs share IPv4 addresses and how that affects home networking.
Read moreGuide
Find your router WAN IP
Locate the internet-facing address shown by your router before you compare it.
Read moreWhat the toolkit helps you answer
Is CGNAT involved?
Compare the router WAN IP with the public IP visible from the web.
Does the port look open?
Try a best-effort TCP reachability check from the public side.
Why is NAT still strict?
Connect NAT type symptoms back to double NAT, UPnP, and forwarding rules.
Quick answers
Common CGNAT questions
What does CGNAT mean?
CGNAT stands for Carrier-Grade Network Address Translation. It lets an ISP place many customers behind shared public IPv4 addresses instead of assigning a unique public IPv4 address to each customer.
Can this checker prove that I am behind CGNAT?
No. This is a best-effort browser check. It can highlight strong signs of CGNAT, but it cannot confirm every network layout or ISP setup from the browser alone.
Why does a private WAN IP matter?
If your router shows a private or shared CGNAT address on its WAN or internet page, that usually means another layer of NAT exists upstream. In many cases that prevents direct inbound connections and port forwarding from working as expected.