Book Image

Learn Wireshark, - Second Edition

By : Lisa Bock
5 (1)
Book Image

Learn Wireshark, - Second Edition

5 (1)
By: Lisa Bock

Overview of this book

Wireshark is a popular and powerful packet analysis tool that helps network administrators investigate latency issues and potential attacks. Over the years, there have been many enhancements to Wireshark’s functionality. This book will guide you through essential features so you can capture, display, and filter data with ease. In addition to this, you’ll gain valuable tips on lesser-known configuration options, which will allow you to complete your analysis in an environment customized to suit your needs. This updated second edition of Learn Wireshark starts by outlining the benefits of traffic analysis. You’ll discover the process of installing Wireshark and become more familiar with the interface. Next, you’ll focus on the Internet Suite and then explore deep packet analysis of common protocols such as DNS, DHCP, HTTP, and ARP. The book also guides you through working with the expert system to detect network latency issues, create I/O and stream graphs, subset traffic, and save and export captures. Finally, you’ll understand how to share captures using CloudShark, a browser-based solution for analyzing packet captures. By the end of this Wireshark book, you’ll have the skills and hands-on experience you need to conduct deep packet analysis of common protocols and network troubleshooting as well as identify security issues.
Table of Contents (28 chapters)
1
Part 1 Traffic Capture Overview
6
Part 2 Getting Started with Wireshark
11
Part 3 The Internet Suite TCP/IP
16
Part 4 Deep Packet Analysis of Common Protocols
21
Part 5 Working with Packet Captures

Exploring the encapsulation process

Now that we have gained an understanding of the layers, let's look at how each of the layers works together during the encapsulation process to create a frame.

During frame formation, the process begins with data. As the data moves down the layers, a header is added, one by one, until the frame is complete. Each frame has the following components:

  • Data and an appropriate Application layer header (if applicable)
  • A segment header
  • A packet (or IP) header
  • A frame header

We'll start with the data portion of the frame.

Viewing the data

In most cases, when frame formation begins and encapsulation takes place, we start with the data, as shown here:

Figure 8.6 – The encapsulation process—data

The data might be any of the following:

  • An HTTP GET request
  • A DNS request to resolve a hostname to an IP address
  • A DHCP broadcast to request a dynamically assigned IP...