Hi, everyone.
My name is Nick Russo, and welcome to Pluralsight's deep dive course on ICMP.
Whether you are a complete newbie to networking or a seasoned engineer,
I'm confident you'll learn a thing or two.
Let's dive in.
In this module,
we begin with the world's shortest monologue on what ICMP is and why it exists.
I don't like to waste time,
so I immediately demonstrate how ping works within the
context of an existing IP network.
This is a deep dive course.
That implies detailed packet analysis.
We break open ICMP echo‑request and echo‑reply messages here.
Last,
we will explore a troubleshooting strategy using
ping that works in any environment.
I promise this will be the shortest explanation of ICMP you've ever heard.
ICMP stands for Internet Control Message Protocol,
which is a clear and self‑evident name.
ICMP does in fact provide a suite of control messages.
In this course, we will explore several of them.
ICMP is defined in RFC 792, which is older than I am.
It's a long and detailed read, so I suggest using it as a reference only.
While ICMP contains many message types used for a variety of purposes,
most engineers immediately think of ping,
the most common ICMP‑based utility.
That is what we are exploring first.
First, some context.
You and I work as network engineers at Globomantics,
a large corporation currently growing through acquisition.
All of the blue objects are devices in our existing network.
We recently acquired Wired Brain Coffee Company to expand our
product portfolio through diversification.
Their equipment is shown in orange.
For the time being, the network is IPv4 only,
and I've added some simple device names to the devices shown.
Because this is a course on ICMP as a protocol and not a course on
specific operating systems or their command lines,
all devices in this network are running Cisco IOS.
That just simplifies the demonstrations and keeps the focus on ICMP where it belongs.