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

TCP connection problems


When two TCP processes wish to communicate, they open the connection, send the data, and then close the connection. This happens when you open a browser to the Internet, connect from your mail client to the mail server, or connect with Telnet to your router or any other application that works over TCP.

When TCP opens the connection, it sends a request for open connection from the source port to destination port.

Some problems can occur during the establishment or closing of the application. Using Wireshark to locate and solve these problems is the goal of this recipe.

Getting ready

If you experience one of the following problems, use Wireshark in order to find out what is the reason for it.

These problems can be of many types. Of these:

  • You try to run an application and it does not work. You try to browse the Internet and you don't get any response.

  • You try to use your mail but you don't have a connection to the mail server.

  • Problems can be due to simple reasons, such as...