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

Comparing request and response messages

When interacting with a web page, a client will request objects from a server. In most cases, a standard transaction involves a request from the client and then a response from the server. Because the client and the server both convey a different message, the headers are slightly different. In this segment, we'll take a high-level view of the HTTP header and fields for both the client and the server.

Let's start by examining the elements of an HTTP request.

Viewing an HTTP request

When viewing a client request, you will most likely see a request line followed by header lines, as shown in the following diagram:

Figure 15.4 – HTTP request format

Each request message will indicate the method (such as GET or POST) and the URL, along with additional parameters. It's also common to see the following:

  • The \r symbol, which is used to indicate a carriage return
  • The \n symbol, which...