What is port sniffing in computer networks?
All computers have 65535 “ports” or “channels” that are used in conjunction with network protocols for communication to other computers. For web pages when you request a website http://yahoo.com Yahoo’s server is “Listening” on port 80 for that request. Your web browser as a default sends that request to port 80 and you get the web page back. Different ports are used for different types of communication. If you run an FTP program, they normally use Port 21. A Telnet Program normally uses Port 22 DNS uses port 53 https uses port 443 For a full list of Common ports see http://www.iana.org/assignments/port-num… Port scanners are tools to look at another computer and report what ports are open on that other computer (or yours if run local). Admins may run them to see what computers on the system have ports open that are security issues or have “open” services that shouldn’t be running.
