PACKET SNIFFERS
A packet network protocol analyzer is a network tool which collects copies of packets from network and analyzes them. It can give network administrator with valuable information for diagnosing and also resolving networking issues. In wrong hands, a sniffer can be used to snoop on network traffic.
To use packet sniffer legally, administrator should be on network which organization owns, be under direct authorization of owners of network, and have knowledge and consent of content creators.