When any data is to be transmitted over a computer network, it is broken down into smaller units at the sender’s node called data packets and re-assembled at receiver’s node in the original format. It is the smallest unit of communication over a computer network. The act of capturing data packet across the computer network is called packet sniffing. It has legitimate uses to monitor network performance or troubleshoot problems with network communications. However, it is also widely used by hackers and crackers to gather information illegally about networks they intend to break into.

Packet sniffing is done by using a software or device called packet sniffer. Using a packet sniffer, it is possible to capture data like passwords, IP addresses, protocols being used on the network, and other information that can help the attacker infiltrate the network. A packet sniffer is a utility that sniffs without modifying the network’s packets in any way. To prevent packet sniffing the user should encrypt the data sent or received. User should use only trusted Wi-Fi networks and regularly scan the network for dangers or issues.