Publisher Summary This chapter discusses the basics of networking, Ethernet, the OSI model, and the hardware that is used in network architecture and a variety of methods used to protect data from eavesdropping by sniffers. Network analysis is the process of capturing network traffic and inspecting it closely to determine what is happening on the network. Network analysis is the key to maintaining an optimized network and detecting security issues. Proactive management can help find issues before they turn into serious problems and cause network downtime or compromise confidential data. In addition to identifying attacks and suspicious activity, a network analyzer can be used to identify security vulnerabilities and weaknesses and enforce the company's security policy. Sniffer logs can be correlated with IDSs, firewalls, and router logs to provide evidence for forensics and incident handling. A network analyzer allows one to capture data from the network, decode the information, and view it in an easy-to-understand format. A network analyzer is a combination of hardware and software. System administrators, network engineers, security engineers, system operators, and programmers all use network analyzers, which are invaluable tools for diagnosing and troubleshooting network problems, system configuration issues, and application difficulties. It is important to remain up-to-date on the latest security technologies, encryption algorithms, and authentication processes to protect against sniffing.