Book Image

Network Analysis using Wireshark 2 Cookbook - Second Edition

By : Nagendra Kumar Nainar, Yoram Orzach, Yogesh Ramdoss
Book Image

Network Analysis using Wireshark 2 Cookbook - Second Edition

By: Nagendra Kumar Nainar, Yoram Orzach, Yogesh Ramdoss

Overview of this book

This book contains practical recipes on troubleshooting a data communications network. This second version of the book focuses on Wireshark 2, which has already gained a lot of traction due to the enhanced features that it offers to users. The book expands on some of the subjects explored in the first version, including TCP performance, network security, Wireless LAN, and how to use Wireshark for cloud and virtual system monitoring. You will learn how to analyze end-to-end IPv4 and IPv6 connectivity failures for Unicast and Multicast traffic using Wireshark. It also includes Wireshark capture files so that you can practice what you’ve learned in the book. You will understand the normal operation of E-mail protocols and learn how to use Wireshark for basic analysis and troubleshooting. Using Wireshark, you will be able to resolve and troubleshoot common applications that are used in an enterprise network, like NetBIOS and SMB protocols. Finally, you will also be able to measure network parameters, check for network problems caused by them, and solve them effectively. By the end of this book, you’ll know how to analyze traffic, find patterns of various offending traffic, and secure your network from them.
Table of Contents (20 chapters)

UDP principle of operation

UDP is a lightweight transport layer protocol that works on a best effort basis. UDP is a good choice of transport layer protocol for end applications that can tolerate packet loss or if the reliability can be taken care of at the application layer. For example, Trivial File Transfer Protocol (TFTP), which is a simple file transfer protocol, leverages UDP as the transport layer protocol. TFTP sends acknowledgement for each block of datagrams received at the application layer. So, even though UDP does not have an inbuilt reliability mechanism, such applications can still use UDP as the transport layer protocol.

The protocol field of the IP header will be set to 17 for UDP. The format of the UDP header is as follows:

Figure 11.1: UDP header format

The host that originates the UDP stream will use any local unused port from range 1024 to 65535. The destination...