Check whether a port on your IP or server is reachable from the internet: Minecraft, RDP, SSH, web servers, cameras.
Defaults to your IP: 216.73.216.200. Up to 12 ports per check; ranges up to 10 ports (e.g. 8000-8010).
Enter an IP or domain and a port — our server tries a TCP connection from the internet, exactly like any outside user. “Open” = the service accepts connections; “Closed” = the host refused; “No answer” = a firewall or NAT drops packets.
Usually: no port forwarding on your router, Windows Firewall/iptables blocks it, your ISP uses CGNAT (no public IP), or the app only listens on 127.0.0.1.
Compare the WAN IP in your router with the IP shown on 10ips.com. If they differ or the WAN address is in 100.64.0.0/10, 10.x or 192.168.x, you are behind carrier NAT and inbound connections won't work.
No — UDP is connectionless, so it can't be reliably verified from outside. The check is TCP only.