Scanning : What Is Port Scanning ?

Many time ago we scanned the different ports making telnet manually. Today people use more sophisticated programms with massive methods to scan IP ranges searching a lot of ports.
Scanning is the process of finding out open /close ports ,vulnerabilities in remote system, server & networks. Scaning will reveal IP addresses, operating system , Services running on remote computer.

There are three types of scanning

1. Port Scanning

2. Network Scanning

3.Vulnerability Scanning

Port Scanning  : Port scanning is one of the most popular technique attacker use to   

                                  discover the service they break into.

>> All the machines connected to a LAN or connected to internet  via modem run many . 

      services that listen at well-known and not so well known ports

>> There are 1 to 65535 ports are available in the computer .

>> By port scanning the attacker finds which ports are available.

Ports : The port numbers are unique only within a computer system.

>> Port number are 16-bit unsigned numbers.

>> The port numbers are devided into three ranges.

1. Well known ports  ( 0.....1023)

2. The registered ports  ( 1024........49151)

3. The Dynamic and/or private ports (49152....65535)

Some well known ports:

>> echo                        7/tcp          Echo

>> ftp-data                  20/udp      File transfer (Default Data)

>> ftp                            21/tcp       File transfer (Control)

>> ssh                           22/tcp       SSH Remote login Protocol

>> Telnet                     23/tcp       Telnet

>> domain                    53/udp      Domain name server

>> www-http               80/tcp       World Wide Web Http

>>Smtp                         25/tcp       Simple mail transfer protocol

>>Whois                       43/tcp        whois server

Some registered Ports:

>> wins                         1512/tcp                   Microscope windows internet name service

>> radius                      1812/udp                 RADIUS authentication protocol

>> yahoo                       5010                         yahoo! Messenger

>> x11                           6000-6063/tcp      X Windows System

Visit the next Topic Nmap Port Scanner