Introduction
In this chapter we will learn how to analyze Layer 3 (IP) and Layer 3 to Layer 2 resolution (ARP). We will discuss the Internet Protocol (IP), Address Resolution Protocol (ARP), Dynamic Host Configuration Protocol (DHCP), routing issues and others, and the problems that you might face while troubleshooting these protocols.
We will start with presenting the protocol's normal behavior for the various protocols and continue with showing what can go wrong and how to solve it.
In general, when we analyze a network problem, we will go bottom up: if you cannot get connectivity, look for the problem in the following order:
Layer 1: Check if the cable is connected and the link LED on the switch and your PC is turned on. This step is to be executed manually.
Layer 2: Check if ARP has discovered the MAC address of the destination. In case of a remote location, check for connectivity between every two nodes/routers on the way. This can be executed with the command line (look at the ARP recipe...