Book Image

Network Analysis using Wireshark Cookbook

By : Yoram Orzach
Book Image

Network Analysis using Wireshark Cookbook

By: Yoram Orzach

Overview of this book

Is your network slow? Are your users complaining? Disconnections? IP Telephony problems? Video freezes? Network analysis is the process of isolating these problems and fixing them, and Wireshark has long been the most popular network analyzer for achieving this goal. Based on hundreds of solved cases, Network Analysis using Wireshark Cookbook provides you with practical recipes for effective Wireshark network analysis to analyze and troubleshoot your network. "Network analysis using Wireshark Cookbook" highlights the operations of Wireshark as a network analyzer tool. This book provides you with a set of practical recipes to help you solve any problems in your network using a step-by-step approach. "Network analysis using Wireshark Cookbook" starts by discussing the capabilities of Wireshark, such as the statistical tools and the expert system, capture and display filters, and how to use them. The book then guides you through the details of the main networking protocols, that is, Ethernet, LAN switching, and TCP/IP, and then discusses the details of application protocols and their behavior over the network. Among the application protocols that are discussed in the book are standard Internet protocols like HTTP, mail protocols, FTP, and DNS, along with the behavior of databases, terminal server clients, Citrix, and other applications that are common in the IT environment. In a bottom-up troubleshooting approach, the book goes up through the layers of the OSI reference model explaining how to resolve networking problems. The book starts from Ethernet and LAN switching, through IP, and then on to TCP/UDP with a focus on TCP performance problems. It also focuses on WLAN security. Then, we go through application behavior issues including HTTP, mail, DNS, and other common protocols. The book finishes with a look at network forensics and how to search and find security problems that might harm the network.
Table of Contents (23 chapters)
Network Analysis Using Wireshark Cookbook
Credits
About the Author
Acknowledgments
About the Reviewers
www.PacktPub.com
Preface
Index

The Expert Infos window and how to use it for network troubleshooting


The Expert Infos window provides us with a list of events and network problems discovered by Wireshark. In this recipe, we will learn how to start the Expert Infos window and how to refer to the various events.

Getting ready

Start Wireshark, and start a live capture or open an existing file.

How to do it...

To start the Expert Infos window, perform the following steps:

Navigate to the Analyze menu and click on Expert Info. The following window will open:

Now you can choose any one of the upper bars: Errors:, Warnings:, Notes:, Chats:, Details:, or Packet Comments:.

Tip

The number at the right-hand side of the bar shows the number of events in this category.

The upper bars give you the following information:

  • Errors: These are serious problems, mostly malformed packets or missing fields in a protocol header. These can be malformed packets of various types such as malformed SPOOLSS, GTP, or others. These can also be bad checksum errors...