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Port check: is your port open?

We try to connect to a port on your own address from the outside, so you can see whether port forwarding and firewall are right.

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  • No tracking, no ads
  • Only your own address

Your address

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Popular ports

What the results mean

Open: a program accepted the connection, the port is reachable from outside. Closed: your computer or router refused the connection; forwarding is in place but nothing listens on the port (the service is not running or listens on another port). Filtered: no answer within five seconds, usually a firewall drops the request or the port forwarding on the router is missing.

We test TCP. UDP ports (Bedrock, Valheim, many voice servers) cannot be tested reliably this way: without a matching answer from the program, an open UDP port looks the same as a filtered one.

Why only your own address?

A port checker for arbitrary addresses is a tool for probing other people's machines. We therefore only test the address your request comes from. If you come in over IPv6, we test your IPv6 address. There is no port forwarding there; instead the router firewall has to open the port for the device.

Behind DS-Lite or CGNAT you share your IPv4 address with other customers of your provider, IPv4 port forwarding is not possible there. Then only IPv6, a tunnel or a server of your own will help.

FAQ

Is the port check safe?

We open a single TCP connection and close it again immediately. No data is sent and nothing is stored apart from short-lived counters against abuse.

The port is "filtered" although I forwarded it.

Check the firewall on the device itself (Windows Firewall, ufw, iptables), whether the forwarding points to the right internal IP and whether your connection has a public IPv4 of its own (no DS-Lite/CGNAT).

Why is my IP different from the one in my router?

If your router shows an address from 100.64.0.0/10 or a private range, you are behind your provider's NAT (CGNAT). We then see the provider's address, not yours.

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