What is a network scanner?

Overview

A network scanner is a software tool that scans the entire network and its nodes for the following:

• Identify connected devices
• Find possible loopholes
• Scan, assess, and evaluate the strength of the network

It is an essential component of network scanning that allows the admin to gather information about the network and its endpoints. Regular network scanning helps the system with the following:

• Maintenance
• Management
• Monitoring
• Security assessment

Working

Network scanning identifies and examines the state as well as the interaction of all the active hosts connected to the network. It then maps them to their IP addresses.

• A packet or a ping is sent to a range of IP addresses, automatically or manually specified by the admin.
• All the hosts that respond to the packets are considered active, while the rest are labeled inactive.
• The responses received are scanned by the software and checked for inconsistencies.
• If any anomaly is detected, it's reported to the manager.

Note: Nmap is network scanning tool that uses IP packets to map the devices attached to the network.

Protocols

Numerous protocols can be used in network scanning depending upon the administration and network requirements. Following are some of the protocols:

• Address Resolution Protocol (ARP): Administration can manually ping the subnet using an ARP scan.
• Internet Control Message Protocol (ICMP): We can map the network topology using ICMP.

Components

Network scanning has two components—port scanning and vulnerability scanning.

Port scanning

The network scanner sends data packets to a specific service port number. This helps in identifying network services available for the particular system.

Data received from the active hosts are used to assess the security levels of an organization.

Vulnerability scanning

The network scanner identifies weak spots and vulnerabilities in the operating system and application software in this scan.

Note: Cyber criminals use network scanning to identify loopholes in the system and prepare for an attack accordingly.

Benefits of network scanning

• It allows the organization to stay aware of the available UDP and TCP services.
• It allows the organization to identify and protect against cyberattacks.
• It allows the organization to increase network performance.
• It allows the organization to identify the filtering systems being used between the nodes.
• It allows the organization to access the operating systems of active devices through their response.