Open port checker
The service checks whether the given TCP port is reachable from the outside — exactly as the internet sees it. Useful when you need to confirm a port is forwarded on your router, a service is open on your server, or your ISP is not blocking it.
Only check devices and servers you own, or resources whose owners gave you permission to test. The service rate-limits requests to protect third-party networks from scanning.
Why check ports
A port counts as open when a running service answers on it and nothing along the way — a firewall, router or ISP — blocks the path. Typical cases: port forwarding for a camera or a torrent client (checking your NAT setup), publishing a game or personal server, and troubleshooting “RDP/SSH won’t connect”. If the port is closed, either no service is running or a block kicks in at one of the layers.
Frequently checked ports: 80 (HTTP), 443 (HTTPS), 22 (SSH), 3389 (RDP), 25565 (Minecraft), 51820 (WireGuard).