Network Scanning

What Does Network Scanning Mean?

Network scanning refers to the use of a computer network to gather information regarding computing systems. Network scanning is mainly used for security assessment, system maintenance, and also for performing attacks by hackers.


The purpose of network scanning is as follows:

  • Recognize available UDP and TCP network services running on the targeted hosts
  • Recognize filtering systems between the user and the targeted hosts
  • Determine the operating systems (OSs) in use by assessing IP responses
  • Evaluate the target host’s TCP sequence number predictability to determine sequence prediction attack and TCP spoofing

Techopedia Explains Network Scanning

Network scanning consists of network port scanning as well as vulnerability scanning.

Network port scanning refers to the method of sending data packets via the network to a computing system’s specified service port numbers (for example, port 23 for Telnet, port 80 for HTTP and so on). This is to identify the available network services on that particular system. This procedure is effective for troubleshooting system issues or for tightening the system’s security.

Vulnerability scanning is a method used to discover known vulnerabilities of computing systems available on a network. It helps to detect specific weak spots in an application software or the operating system (OS), which could be used to crash the system or compromise it for undesired purposes.

Network port scanning as well as vulnerability scanning is an information-gathering technique, but when carried out by anonymous individuals, these are viewed as a prelude to an attack.

Network scanning processes, like port scans and ping sweeps, return details about which IP addresses map to active live hosts and the type of services they provide. Another network scanning method known as inverse mapping gathers details about IP addresses that do not map to live hosts, which helps an attacker to focus on feasible addresses.

Network scanning is one of three important methods used by an attacker to gather information. During the footprint stage, the attacker makes a profile of the targeted organization. This includes data such as the organization’s domain name system (DNS) and e-mail servers, in addition to its IP address range. During the scanning stage, the attacker discovers details about the specified IP addresses that could be accessed online, their system architecture, their OSs and the services running on every computer. During the enumeration stage, the attacker collects data, including routing tables, network user and group names, Simple Network Management Protocol (SNMP) data and so on.


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Margaret Rouse
Technology Expert

Margaret is an award-winning technical writer and teacher known for her ability to explain complex technical subjects to a non-technical business audience. Over the past twenty years, her IT definitions have been published by Que in an encyclopedia of technology terms and cited in articles by the New York Times, Time Magazine, USA Today, ZDNet, PC Magazine, and Discovery Magazine. She joined Techopedia in 2011. Margaret's idea of a fun day is helping IT and business professionals learn to speak each other’s highly specialized languages.