Original subtitles

What's up everybody.

So I'm going to preface this video really quick with that it is raining pretty hard here so if the soothing

sounds of the rain put you to sleep during this video and you can hear it I'm very very sorry but the

show must go on.

So we're gonna be doing today is there going to be talking about IP addresses.

Now if you've ever used a computer before and you're any anyone familiar with I.T. you probably know

an IP addresses.

But I want to take this a little bit deeper in in theory on why we use IP addresses what types of IP

addresses are out there and talk more about protocols and how IP addresses are actually designed and

made up.

So I'm here in a Cowley terminal and I'm just going to type in a simple command in that command is i

f config.

Now if you've used Linux before this might be familiar to you if you use Windows.

It's similar to IP config.

All I'm trying to do is bring up my IP address so we can see here is that we have an IP address which

is our iiNet.

This is my IP address here.

I also have another IP address.

This iiNet Six this is what's called an IP B address.

So we've got this iiNet which is considered an IP before in this iiNet 6 which is considered IP v 6.

Now you can notice right away that there's two different types of notations for these this iiNet here

is in a decimal notation and the IP 6 is in a hexadecimal notation.

We'll get to the importance of that in just a second.

So when it comes to IP addresses this looks probably pretty familiar to us.

This is an IP address.

This is how we communicate.

We communicate over Layer 3 and you're going to hear we talking about layers repeatedly throughout the

course or at least throughout this part of the course.

So that we can get familiar with how we're actually doing this.

So I want you to be familiar with troubleshooting these layers and these layers all refer to something

called the os sy model.

So when we talk about layers we think about the LSI model and I'll introduce the LSI model here in a

few videos and it should all click.

Once I introduce the ISI model so if I brought in the LSI model up front it might be boring might not

make sense.

Some introduce the OS model near the end and say hey yeah that all makes sense.

So what we've got here is we've got this IP for address and this is the most commonly use format that

we use today right.

We use IP for mostly everything.

And again this isn't that decimal notation.

So when we see this decimal notation it's just a realistically a bunch of ones and zeros that are put

together so that we have this human readable format.

Realistically all we're seeing here with one ninety to this first this first section here this first

octet is actually just a bunch of ones and zeros it's eight bits.

So we've got a range of eight ones and zeros here.

We've got another eight here eight here and eight here.

So when it's all said and done this iiNet or this IP v four is made up of 32 bits eight plus eight plus

eight plus eight here and which equals four bytes.

So another way to think about that is to think about it as say something like this.

One two three four five six seven eight.

Period.

OK.

That is one section there.

So we've got eight ones that can make up this.

And then we'd have another eight et cetera.

Not going to beat a dead horse here but I do want to give you guys another example.

So if we go into our applications and we go to a text editor really quick.

So the way this looks is something like this.

We start with a number like 128 to spaces out as best as possible.

And all I like to do is think of 128 as my base and this will make a lot more sense when we get into

the subducting so please if you're confused by this Don't worry this is all theory right now.

When we get into sub meaning we get hands on it I'll make a lot more sense I promise you.

So let's say we have ones and zeros here.

If we have a one for each of these sections and I'm going to spaces out again as best as possible it's

not pretty but if we have a one for all these this equals two fifty five why does this equal to fifty

five.

Well you take this and all these numbers add up one plus two plus four plus eight all this adds up to

255.

So let's say if we didn't have all the ones zeros we had just some ones enabled like these last three

here.

OK.

Well this one equals seven because we have four plus two plus one equals seven.

So our first number or whatever number this apply to in the Octet will be seven.

So if we had seven seven seven seven it would just this numbers repeating over and over these numbers

repeating over and over.

Right.

So be 0 0 0 0 1 1 1 dot 0 0 0 0 1 1 1 and so forth.

So this is kind of what it looks like behind the scenes because again a computer is just ones and zeros

we're all binary so we're going to do is we're in closes out or talk a little bit of other theory when

it comes to this and why I net or HPV 6 and why ITV 4 so let's close this and let's talk about IP for

somebody bring up a calculator and with IP before we have these 32 bit.

So what we can do is we could take two to 30 second power and this is the possible amount of IP addresses

that we could have.

So we have somewhere in the 4 billion range of IP addresses.

Well spoiler alert we don't have only four billion people on earth right where we're up to seven something

billion at this point.

And all these IP address spaces are gone.

So ITV 4 has been around since 1981.

Nobody thought we were ever going to use all these addresses.

Computers weren't really a thing.

Who knew that we were going to want all these addresses.

And you know at these companies started buying them up and they started buying them up in large chunks

and then they sold those to ISP fees and then ISP sell those to you.

And so these IP addresses have been gone for a very very long time and chances are when you when you

have an IP address and you get this IP before you're only going to get one if you're a corporation you

might buy more.

But we've run out of IP address space.

There's just not enough to go around.

So the theory is OK let's come up with something different.

Let's come up with IP 6.

Now this hexadecimal is actually in one hundred and twenty eight bits which makes things just a little

bit longer and adds quite a bit.

So let's take this two to one hundred twenty eight power and we get a number that I can not tell you

how to say nine I'm going to try but I can guarantee you that in our lifetime we will never use this

address based so we've come up with the solution of IPD sex but nobody really uses it.

IPD 6 is just a thing that's there.

But when we we get IP these six addresses a sign but still to this day everybody's using IP before.

Well how how is that possible.

If we're using IP before but we're out of address space.

Well think about this.

We're using something called net which is network address translation.

Now let's think about your network.

So you might have a cell phone or computer or multiple devices my network has at least 20 devices on

it I've got I've got cameras I've got multiple cell phones smart TV is everything that connects to my

Internet gets an IP address and that's 20 IP addresses right there.

Right.

So let's say I have 20 devices that's 20 IP addresses.

Am I taking up 20 IP addresses out of that 4 billion.

No.

We're actually using something called network address translation or it's called net for short.

And we'll talk about this again when we we set up our actual lab.

But with that what we're doing is we're assigned these private IP address spaces.

So we've got this 1 9 2 1 6 8 dot fifty seven dot one thirty nine.

Now if you've ever seen a IP address before and you've been on a network good chances are it probably

started with one ninety two.

Or maybe it started with a 10 dot or something along those lines.

And that's because those are private IP addresses.

So anything that starts with 1 9 2 1 6 8 is not an IP address that is going to be out in the the interweb.

It is going to be an IP address that is only known to you.

These are called private IP addresses.

So because we use these private IP addresses we can pass them out through what is called a public IP

address.

Now to make better use of this let's go out to Firefox I've already got a tab open so I went to Google

and I just said private IP addresses and I clicked the second image here because I think it's a great

image.

So if we look at this there are classes of IP addresses private IP addresses.

Now there is a Class D and E.

We're not going to worry about those the big three are Class A B and C if you know these you are are

good to go.

So if we look at Class C this is what the most common household and small business use.

So we see it starts with the 1 9 2 1 that 0 0 so the 1 9 2 168 are constant.

If you see a 1 9 2 1 6 8 address you can guarantee yourself that that is a private IP address base.

And then we have the range of changing this number between 0 and 255 and this number between 0 and 255

y 0 to 255.

Well that'll all make sense when we get into submitting.

But what that allows us to do is have a large number of networks here and a small amount of hosts.

But for a a regular user like you or I or a small business two hundred fifty four hosts is pretty good.

I mean I'm only using 920 20 in my household.

So the most common household is probably using this 1 9 to address.

But what about a big big business.

Right.

Something huge.

OK well they might use a 10 address because a 10 address frees you up to anything after this 10 is private.

So 10 dot 1 10 not one dot one dot one whatever you want to put in here up to two fifty five on each

octet makes for a small amount of networks but a large amount of hosts.

OK.

And don't worry about the hosts Versus network thing again submitting.

We'll talk about that.

It all makes sense.

But just imagine the amount of amount of hosts that you can get in here with this wide range.

So because of this you'll see larger corporations using 10 addresses.

You'll also see a lot of corporations even small businesses using 10 addresses the the matter of fact

is as long as you have this private IP address you're good to communicate across your network.

So any IP address outside of these in the loop back here are free game for the public address space.

They're probably already owned and you purchased those or rent those really from your ISP your Internet

service provider.

So going back to this thought we have a classy address my networks Class C 1 9 2 1 6 8 fifty seven one

thirty nine here.

So it falls into that class C I got all these devices on this 1 9 2 1 6 8 network all of these devices

are talking out of one IP address.

That is my public IP address.

That is what I rent from my ISP and all this network traffic goes out one ip.

So this is how we have achieved or solve the issue of running out of address space without having to

use IP B6.

Now there's anything wrong with IP these six.

It's not pretty.

I mean it's way easier to type this stuff in than it would be to take something like this in.

But at the same time this is how we've solved it.

We've eight we're able to still use IP before and mostly all networks and we are able to communicate

out with this quote unquote IP address shortage.

So hopefully that makes sense.

We're going to build upon these concepts again.

IPTV for IP 6.

IP addresses are Layer 3 protocols Layer 3 is a router.

So when we route traffic we route via an IP address.

So we're gonna build upon that as well as we go in.

Hopefully this is all just a refresher to you.

So that is it for this video.

I'll go ahead and catch you over in the next one.