What is Free Port Scanner?
A free port scanner is a software tool that computer professionals, network administrators, and security researchers use to scan open ports on devices on a network. It works by systematically sending requests to ranges of TCP and UDP ports on targeted machines and listening for responses to determine which ports are open, closed, or filtered.
Free port scanners can scan ports on your own computer to inventory services and applications listening for connections. They are also useful for probing remote hosts and networked devices to check for vulnerabilities, backdoors listening on unusual ports, misconfigurations in firewall rules, and more. The information a port scan provides can help identify security risks that need to be addressed.
Unlike expensive commercial port scanners, free tools like Angry IP Scanner, Advanced Port Scanner, and Nmap have basic but sufficient features for most scanning needs. They can scan hundreds or thousands of ports rapidly on multiple hosts at once and usually allow some control over advanced scan types, port ranges, reporting, and other options.
While lightweight free scanners may lack a graphical interface or active scanning features found in paid products, they get the job done for assessing simple security risks. And their approachable interfaces allow even novice computer users to understand and remediate problems found during scanning.