Network Scanning refers to a set of procedures performed to identify hosts, ports, and services running in a network.
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.
Source:
https://www.techopedia.com/definition/16124/network-scanning