Book Image

Wireshark Revealed: Essential Skills for IT Professionals

By : James H Baxter, Yoram Orzach, Charit Mishra
Book Image

Wireshark Revealed: Essential Skills for IT Professionals

By: James H Baxter, Yoram Orzach, Charit Mishra

Overview of this book

This Learning Path starts off installing Wireshark, before gradually taking you through your first packet capture, identifying and filtering out just the packets of interest, and saving them to a new file for later analysis. You will then discover different ways to create and use capture and display filters. By halfway through the book, you'll be mastering Wireshark features, analyzing different layers of the network protocol, and looking for any anomalies.We then start Ethernet and LAN switching, through IP, and then move 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. This book finishes with a look at network forensics and how to locate security problems that might harm the network.This course provides you with highly practical content explaining Metasploit from the following books: 1) Wireshark Essentials 2) Network Analysis Using Wireshark Cookbook 3) Mastering Wireshark
Table of Contents (5 chapters)

Chapter 7. Ethernet, LAN Switching, and Wireless LAN

In this chapter we will cover the following topics:

  • Discovering broadcast and error storms
  • Analyzing Spanning Tree Protocols
  • Analyzing VLANs and VLAN tagging issues
  • Analyzing wireless (Wi-Fi) problems

Introduction

In this chapter, we will focus on how to find and resolve layer-2-based problems with the focus on Ethernet-based issues such as broadcast events and errors and how to find out where they are coming from. We will also focus on LAN protocols such as Spanning Tree, VLANs, and Wireless LAN.

These issues have to be resolved before we go up to layers 3, 4, and the Application layers, since layer 2 problems will be reflected in the upper layer protocols. For example, packet losses in layer 2 will cause retransmissions in TCP, which is a layer 4 protocol, and these can cause slow application response time in the upper layers.

Discovering broadcast and error storms

One of the most troublesome problems in communication networks is...