Network analysis is the process of capturing network traffic and examining it closely in order to deduce information from it. A packet sniffer is a hardware device or software that captures, records and analyses network traffic. Network analysis can be used for both good and evil.
Proper uses of network analysis
A network administrator performs network analysis to monitor network usage, analyse network problems and debug client/server communications.
A network security practitioner performs network analysis to detect network intrusion attempts and violations against network usage policies.
Improper uses of network analysis
Hackers perform network analysis to gain information for effecting network intrusion and other unauthorized (and often illegal) activities.
An engineer (or a student like you) can also use network analysis to investigate, study and reverse engineer protocols used over the network.
In the Activity 5 you will use a powerful and free packet sniffer, Wireshark, to capture and analyse the traffic between your PC and selected remote hosts on the Internet. In addition, you will use a wireless networking tool, NetStumbler, to detect the wireless LANs in your neighbourhood. You will be surprised that many people are not running their wireless LANs in secure mode and hence are vulnerable to wireless sniffing.