Port Scanner

What is a Port Scanner?

Imagine every computer is a house. To let people in or send mail out, the house needs doors and windows. In the world of networking, these doors are called Ports.

A Port Scanner is like a digital neighbor who walks around your house and knocks on every door to see if it is unlocked. There are over 65,000 possible doors on every computer! Our tool checks the most common ones to see if they are Open (Unlocked), Closed (Locked), or Filtered (Hidden behind a fence).

How Do Port Checks Work?

When you run our online open port checker, our server sends a "Hello" message to a specific port on your IP address. This is called a TCP Handshake. If your computer says "Hello" back, we know the port is open. If your computer says nothing, it means the door is either closed or you have a Firewall protecting it.

Why is Port Forwarding Important?

If you are a gamer or you have a security camera at home, you might need to "Open a Port" on your router so people can connect to you. This is called Port Forwarding. You can use our scanner to verify that you set it up correctly and that your device is reachable from the internet.

Common Ports to Watch

• Port 80 & 443: These are used for browsing websites. Almost every web server has these open.
• Port 21 (FTP): Used for sending files. This is an old door and should be used with care.
• Port 3389 (RDP): This allows someone to control your computer remotely. Be very careful if this door is open!
• Port 3306 (MySQL): This is for databases. Usually, this should stay closed to the public.