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

Understanding the expression builder

In addition to building simple display filters, Wireshark has the ability to create an expression that zeroes in on specific field values. To build an expression, go to Analyze and then select Display Filter Expression, as shown here:

Figure 7.18– The Display Filter Expression menu choice

Click the link to launch the expression builder. On the left-hand side, you will see a list of all of Wireshark's supported protocols, as shown in the following screenshot:

Figure 7.19 – Display Filter Expression

Wireshark is capable of dissecting hundreds of protocols with more added all the time, so the list will be long.

To further refine the filter, you can select from the four variables listed on the right-hand side:

  • Relation: This is a list of comparison operators to compare a field value against another value using logical operators:
    • is present: Indicates the selected field...