In computer networking (defined by RFC 793 and standard TCP/IP architecture), a port is a virtual 16-bit communication endpoint (numbered from 1 to 65,535). While your public IP address directs internet traffic to your modem or router, port numbers ensure data packets reach the exact application intended—such as port 80 for web browsing, port 22 for SSH server administration, or port 25565 for Minecraft multi-player games.
By default, home routers use Network Address Translation (NAT) and built-in stateful firewalls to block all unsolicited incoming connections from the public internet. If you want external friends or clients to connect to a service hosted on your home computer (such as a Plex media server, camera system, or game server), you must configure Port Forwarding in your router settings. Port forwarding instructs your router to take incoming traffic on a specific port and route it directly to your computer's local private IP address.
Our external port checker originates connection attempts from our cloud infrastructure outside your network. This gives you an accurate, real-world assessment of whether your service is accessible to external users or if your router, ISP, or firewall is blocking incoming traffic.
Verify if external ports are accessible through your home router, firewall, or cloud server. Test Minecraft, Web, SSH, RDP, and Plex connections instantly.