It is similar to a thief going through your neighborhood and checking every door and window on each house to see which ones are open and which ones are locked. similarly computers have ports form 1 to 3000 ports for communication
- 21: FTP
- 22: SSH
- 23: Telnet
- 53: Domain Name System
- 80: World Wide Web HTTP
- 119: Network News Transfer Protocol
- 443: HTTP over Transport Layer Security/Secure Sockets Layer
- 445: microsoft-ds, Server Message Block over TCP
Port Scanners :-
Nmap :- This tool developed by Fyodor is one of the best unix and windows based port scanners. This
advanced port scanner has a number of useful arguments that gives user a lot of control over the
Latest Release:- Nmap 5.00
Superscan :- A Windows-only port scanner, pinger, and resolver SuperScan is a free Windows-only closed-source TCP/UDP port scanner by Foundstone. It includes a variety of additional networking tools such as ping, traceroute, http head, and whois.
Angry IP Scanner :- A fast windows IP scanner and port scanner. Angry IP Scanner can perform basicHome:- http://www.foundstone.comLatest Release:- SuperScan v4.0
host discovery and port scans on Windows. Its binary file size is very small compared to other scanners and other pieces of information about the target hosts can be extended with a few plugins.
Home:- http://www.angryziber.com [sourceforge.net]
Latest Release:- IPScan 3.0-beta3
Unicornscan :- Unicornscan is an attempt at a User-land Distributed TCP/IP stack for information gathering
and correlation. It is intended to provide a researcher a superior interface for introducing a stimulus into and measuring a response from a TCP/IP enabled device or network. Some of its features include asynchronous stateless TCP scanning with all variations of TCP flags, asynchronous stateless TCP banner grabbing, and active/passive remote OS, application, and component identification by analyzing responses.
Latest Release:- Unicornscan 0.4.7-2
If you have any doubts please be free to comment