Port Scanner: Open Port Checker

Verify your network security instantly. Check for open ports on any server or IP address and identify running services like SSH, HTTP, or MySQL.

AI Overview

A port scanner probes an IP address to see which "doors" (ports) are open. Open ports allow services to communicate but can also be security risks if left unprotected. Our tool helps you test firewalls and verify port forwarding configuration for servers and IoT devices.

What is a Port Scanner?

A port scanner is a diagnostic tool that checks which ports on a specific IP address are active and listening for connections. Network ports are numbered from 0 to 65535. Common services like web hosting use Port 80 (HTTP) and Port 443 (HTTPS). Identifying these ports is the first step in auditing your network security.

Security Tip: Every open port is a potential entry point for hackers. Use this tool to ensure that sensitive ports like Port 22 (SSH) or Port 3306 (MySQL) are closed to the public if not needed.

How to Check if a Port is Open

To use our online port checker, simply enter your server’s IP or hostname. Our scanner attempts a TCP handshake with the target ports. If the server responds, the port is marked Open. If the request is ignored, it is labeled Filtered (usually by a firewall).

Why Port Scanning is Useful

  • Firewall Testing: Confirm your firewall rules are correctly blocking unwanted traffic.
  • Port Forwarding: Verify that your router is correctly sending traffic to your game server or NAS.
  • Service Detection: Quickly identify what software (Web server, Mail server, Database) is running on a host.
  • Network Auditing: Periodically scan your own IP to find accidentally exposed services.

Frequently Asked Questions

Is port scanning legal?
Scanning your own devices or servers is 100% legal. Scanning third-party systems without permission may be illegal depending on your local laws.

What does "Filtered" mean?
It means a firewall is dropping the connection attempts silently. The scanner cannot tell if the port is open or closed.

Which ports are most important?
For web users, Ports 80, 443, and 22 are the most common. For remote workers, Port 3389 (RDP) is frequently checked.