Network tool
Port Checker
This test opens a connection from our servers to your public IP address on the port you choose. If something answers, the port is open and reachable from outside your network. It only ever checks your own connection, never someone else's address.
Detecting your IP address…
Why this only checks your own IP.
This tool always tests the connection you're currently using, not an address you type in. That keeps it useful for its real purpose, confirming your own port forwarding, without doubling as a scanner against someone else's server.
How this port check works
When you run a check, our server attempts to open a TCP connection to your current public IP on the port you picked. This is the same idea behind hosting a game server, a self-hosted service, or a remote desktop session: for someone outside your network to reach it, your router needs to forward that port through to the right device. If the connection succeeds, we report the port as open. If nothing answers, or the connection is refused, we report it as closed.
Why we only check your own IP
Some port-checking tools let you type in any address. This one doesn't, and that's deliberate. A public tool that connects to whatever address a visitor types would double as an anonymous port scanner against other people's servers, which isn't something we're willing to run. Checking only the IP address you're currently connecting from keeps this tool useful for its actual purpose, confirming your own port forwarding, without turning it into something that could be pointed at someone else's network.
Open, closed, or blocked: what each result means
Open means something answered on that port and it's reachable from the internet. Closed means either the connection was actively refused, or nothing responded within a few seconds, both usually point to the port not being forwarded or nothing listening on it. Blocked is different: it means the check itself couldn't run, usually because port 25 is restricted at the platform level, or because your connection is routing through a network (for example Cloudflare WARP) that this kind of check isn't allowed to reach. A blocked result isn't a statement about your port, just that we couldn't test it.
If a port you expected to be open shows closed
- Double check port forwarding is set up on your router for the right internal IP address and port, and that the device's local IP hasn't changed since you configured it.
- Confirm the service is actually running and listening on that port. An open forward to a stopped service still shows as closed.
- Check your device's own firewall isn't blocking the incoming connection. Router forwarding and OS firewalls are separate settings.
- Ask your ISP whether you're behind Carrier-Grade NAT (CGNAT). If your router's public IP doesn't match the IP shown on this site, port forwarding can't work no matter how it's configured, because you don't have a real public IP to forward to.