Book Image

Mastering Wireshark 2

By : Andrew Crouthamel
Book Image

Mastering Wireshark 2

By: Andrew Crouthamel

Overview of this book

Wireshark, a combination of a Linux distro (Kali) and an open source security framework (Metasploit), is a popular and powerful tool. Wireshark is mainly used to analyze the bits and bytes that flow through a network. It efficiently deals with the second to the seventh layer of network protocols, and the analysis made is presented in a form that can be easily read by people. Mastering Wireshark 2 helps you gain expertise in securing your network. We start with installing and setting up Wireshark2.0, and then explore its interface in order to understand all of its functionalities. As you progress through the chapters, you will discover different ways to create, use, capture, and display filters. By halfway through the book, you will have mastered Wireshark features, analyzed different layers of the network protocol, and searched for anomalies. You’ll learn about plugins and APIs in depth. Finally, the book focuses on pocket analysis for security tasks, command-line utilities, and tools that manage trace files. By the end of the book, you'll have learned how to use Wireshark for network security analysis and configured it for troubleshooting purposes.
Table of Contents (18 chapters)
Title Page
Copyright and Credits
Packt Upsell
Free Chapter
Installing Wireshark 2

DHCP analysis

In this section, we'll take a look at how DHCP works, some of the fields that are within the DHCP protocol, watch a client retrieve an IP address, and also take a look at what happens with DHCP when a client requests an address and receives responses.

Let's start a packet capture. What we'll do now is release the address on my computer and then renew it.

Type ipconfig /release on a Windows computer on Command Prompt to release our address, then if we type ipconfig /renew, it will get us a new address.

Now, if we type ipconfig /all, we should be able to see that our address is assigned. We'll stop our capture now. We'll want to only pick out the DHCP traffic. So you would assume you could go up to the display filter and type dhcp, just like we've done for the other protocols, and then press Enter and it works. But we can see that there's a red bar up there, which indicates that dhcp is not valid:

This is because the display filter is actually bootp. DHCP is based off of bootp. bootp...