Data sniffing, or packet sniffing, is the covert interception and analysis of data as it moves across a network. While some sniffers serve legitimate purposes (for example, network troubleshooting by administrators), attackers use sniffers to capture sensitive information such as usernames, passwords, financial data, and confidential communications. The stealthy nature of sniffing makes it a prevalent security risk in both corporate and public networks. Defending against sniffing requires a laye...