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- Let's talk about the difference

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between public IP addresses
and private IP addresses.

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Up until now, we've been
talking private IP addresses.

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And an example I've been
using a lot is 192.168.1.1.

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This is a private IP address.

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It means it's supposed
to be used internally

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within your local area network.

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It also means that it does not
face the internet directly.

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That's why it's called private.

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Public addresses, however,

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they do face the internet directly.

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An example would be 65.43.18.1.

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And this IP address is
known as internet facing

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or public facing.

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And that means that
anybody around the world

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can see that IP address.

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Anybody around the world
will not be able to see this

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because it's behind usually a firewall

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and behind some type of network
address translation device.

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When it comes to public addresses

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you have to be very careful with security.

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You wanna secure any servers
that are on public addresses

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to a certain extent.

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You're gonna wanna
leave them open somewhat

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so that people can gain
access to services,

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and everything else you're
gonna want to firewall

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and close down that server,
make sure it's secure.

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And we're gonna show examples
of public IP addresses,

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private IP addresses in Windows
now, or just in a second.

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What I want to show real quick though

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are the private IP ranges
that you should know.

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Besides 192.168, there's
also the 10 network.

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And the 10 network could be anything.

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It could be 10.254.254.0.

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It could be anything after it,

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but it's gonna be something on 10.

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And then the other one,

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which I had mentioned
before is 172.16.x.x.

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That's gonna be the network number.

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Also 172.17 all the way through to 172.31.

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Those are the main private IP numbers

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that you're gonna need to know.

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We're gonna go over those again

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when we look on the computer.

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So let's get into Windows
now and show some examples

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of public and private IP addresses.

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Okay, so we talked about in theory

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public IP addresses versus
private IP addresses

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and the differences between those.

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Now let's show it a little
bit in the command line.

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First of all, let's show
a private IP address.

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If we do a simple ipconfig,

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we'll see once again our ethernet adapter

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and the address 10.254.254.204.

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That address is a private address.

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Anything on the 10 network
is gonna be private.

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That's internal.

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And the only computers

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that are gonna be able to connect
to this are local systems,

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systems on the local area network.

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But you don't have to worry

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about computers on the
internet connecting to you.

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If you want to have a system
that anyone can connect to

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then you want to have some
type of server on the internet

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and then you would want
a public IP address.

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So let's give an example of that now.

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I'm gonna connect to
the example.com domain

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with the ping command,

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which will then show
its public IP address.

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So we'll do a ping and example.com

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and you can see the replies come up now.

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I'm pinging this from my computer,

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but example.com is in a
completely different area

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on the internet.

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And you can see the address
here, 93.184.216.34.

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93 is a public IP address.

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Anything that starts with
the class A 93 network

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is gonna be public.

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So you got a little example
there with example.com

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of a public address.

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Remember, the public
addresses are used by servers

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or any computers that
need to be internet facing

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so that anyone around the
world can connect to it.

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But the private address is
something that you use usually

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for all your local computers,
all your clients on your LAN.

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And an example of that

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is our laptop that we have right here

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that's using the IPv4
address 10.254.254.204.

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So know your differences
between private and public

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and take a look on your own system now

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and take a look at your own address

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and maybe try pinging some
websites and domains out there

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to see their public addresses.

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And that wraps it up for this sub lesson.