Port scanning is a technique used in cybersecurity to identify the open ports on a computer or network. It is a method of sending packets of data to a target device to identify which ports are open and therefore vulnerable to potential attacks.

The purpose of port scanning is to determine the security of a network by identifying any open ports that can be used to gain unauthorized access. By scanning for open ports, an attacker can identify which services are running on a system and potentially exploit vulnerabilities in those services.

Port scanning can be done using both manual and automated methods. Manual port scanning involves using specialized tools to send data packets to a target device and analyze the response to identify open ports. Automated port scanning involves using software tools that scan a range of IP addresses and ports to identify vulnerabilities across multiple systems.

There are several types of port scanning techniques, including TCP scanning, UDP scanning, and full-connect scanning. TCP scanning involves sending a SYN packet to a target device to determine whether a port is open, closed, or filtered. UDP scanning involves sending UDP packets to identify open ports. Full-connect scanning involves establishing a full connection with a target device to determine whether a port is open.

To protect against port scanning attacks, organizations can use firewalls and intrusion detection systems to monitor network traffic and identify potential threats. By limiting the number of open ports and services running on a system, organizations can reduce the risk of potential attacks. Additionally, regularly updating software and applying security patches can help to prevent vulnerabilities that can be exploited by attackers using port scanning techniques.