Sniffing is the practice of monitoring and collecting the data packets that are moving via a particular network. Monitoring and troubleshooting network traffic problems are this tool's primary uses among system and network administrators. You can observe all types of traffic, including protected and unprotected traffic, when you sniff. Attackers use this to collect data packets that include sensitive information including email traffic, FTP password, web traffic, router configuration, DNS traffic, and various other types of traffic. There are two primary categories of sniffing: Active sniffing: In this scenario, not only is traffic restricted and watched, but it also may be changed in some way, depending on how the assault plays out. It is used to sniff traffic on networks that are switch-based. Injecting address resolution packets into a target network in order to turn on the content addressable memory table is a necessary step in this process. Sniffing in a passive manner:  In this scenario, the flow of traffic is restricted but is otherwise unaffected in any manner. It functions with hub devices, and data is distributed to all of the available ports. All of the computers that are connected to the unbridged or non-switched network segment are able to observe all of the traffic that is moving through the segment.