Book Image

Mastering Wireshark 2

By : Andrew Crouthamel
Book Image

Mastering Wireshark 2

By: Andrew Crouthamel

Overview of this book

Wireshark, a combination of a Linux distro (Kali) and an open source security framework (Metasploit), is a popular and powerful tool. Wireshark is mainly used to analyze the bits and bytes that flow through a network. It efficiently deals with the second to the seventh layer of network protocols, and the analysis made is presented in a form that can be easily read by people. Mastering Wireshark 2 helps you gain expertise in securing your network. We start with installing and setting up Wireshark2.0, and then explore its interface in order to understand all of its functionalities. As you progress through the chapters, you will discover different ways to create, use, capture, and display filters. By halfway through the book, you will have mastered Wireshark features, analyzed different layers of the network protocol, and searched for anomalies. You’ll learn about plugins and APIs in depth. Finally, the book focuses on pocket analysis for security tasks, command-line utilities, and tools that manage trace files. By the end of the book, you'll have learned how to use Wireshark for network security analysis and configured it for troubleshooting purposes.
Table of Contents (18 chapters)
Title Page
Copyright and Credits
Packt Upsell
Free Chapter
Installing Wireshark 2

Capturing scenario traffic

In this section, we'll take a look at capturing some traffic for our troubleshooting scenario, and checking for some obvious issues before we look into the packet capture a bit more in-depth.

In the following screenshot, we have captured the traffic from the client connecting to the server:

We will now put a filter in here for port 21 because we know that the client is connecting over standard unencrypted FTP. For that we use tcp.port == 21:

So, we got rid of everything else. We can see that there are three packets, and it looks like we have a SYN and two retransmissions. So the client, which is .152, is trying to connect to the server running on .160, and it's not even beginning the TCP handshake. So the server is not doing something correctly in order to negotiate port 21. It's not that the server is rejecting the user credentials or there's some sort of other obvious issue. It's definitely not listening on 21 or something like that. Let's start a capture on the...