Port Checker

Check open ports on any public IP address with this free Port Checker tool. It lets you verify whether a specific port is open, closed, or unresponsive. This is especially useful for verifying service availability and troubleshooting external network connectivity.

How This Tool Works

This tool performs a port scan by sending a request to the specified port on a target IP address or domain. Based on the response, it provides the status of the port:

• Open: The port is active and accepting incoming traffic, meaning the service running on that port is reachable.
• Closed: The port is not accessible, either because there is no service running on it or it has been intentionally blocked.
• Timeout: The tool did not receive a response, indicating that the port may be blocked by a firewall, router, or other network security measures.

Commonly tested ports include:

• 80 → HTTP (Web Traffic)
• 443 → HTTPS (Secure Web Traffic)
• 21 → FTP (File Transfer Protocol)
• 22 → SSH (Secure Shell)
• 3389 → RDP (Remote Desktop Protocol)
• 25565 → Minecraft (Game Server)

Why Check Open Ports?

Knowing whether a port is open can help pinpoint service availability issues. If something isn't reachable from the internet, a closed or filtered port might be the reason. It's also a good way to ensure that only intended services are exposed, reducing unnecessary security risks.

How to Use This Tool

1. Enter the IP address or domain name to test.
2. Input the port number (e.g., 80, 443, 22).
3. Click the “Check” button to start the scan.

The tool attempts to connect to the selected port and returns whether it's open, closed, or if it times out. A timeout generally means the port is blocked or filtered by a firewall or network device.

Public Access Requirements

This tool can only test ports on devices that are publicly reachable over the internet. If the device is behind a router, firewall, or uses NAT (as in most home networks), you'll need to configure port forwarding for the port to be visible. Without that, even an active service will appear closed.

Extra Tips

• Use tools like netstat, ss, or lsof to check open ports on your local system.
• Ensure firewalls or cloud security groups allow incoming traffic on the port you're testing.
• Set up port forwarding on your router if you're hosting services from a private network.

This Port Checker is a lightweight, browser-based way to diagnose port accessibility and external service reachability - no installation needed.