Port Scan
The purpose of a port scan is to scan the own computer/network on security vulnerabilities or to scan a foreign computer/network to infiltrate it easier. A port scan analyzes the machines of a network on offered services like HTTP, Telnet, FTP, etc. This is possible, because every service has its specific and numeric value (the so called "TCP/UDP port number").
The usual procedure of a port scanner is either try to establish a connection to a service (Connect Scan) or try to get information about the active services by checking the answer sent on invalid packets (Stealth Scan).
