IP Addressing Fundamentals

0:00All right, as we get started in this particular course,

0:02I got to ask you a question.

0:04Where are you in your career?

0:06And what are your goals in your IT career?

0:09Regardless of where you are,

0:10maybe you've been on the help desk

0:11for a couple of years or so,

0:13and you're kind of ready to get off the help desk.

0:15I mean, it's a good entry level,

0:17but a lot of times we don't want to stay there

0:18because we want to move into things that are more advanced.

0:21One of those things that's more advanced,

0:22server, the server world, systems administration.

0:25That's why we're learning more

0:27about Server 2025, Active Directory, all that stuff.

0:31Another big part of it though, is understanding networking.

0:34And this is going to apply

0:36whether you work with Windows Server 2025 as an admin,

0:40or whether you move into other parts of IT,

0:42like network administration, network knowledge,

0:46and a good understanding of these fundamentals

0:49is pretty critical to just about everything.

0:51I can't remember the last time I worked with a server

0:54or really even a client that was strictly cut off

0:57from any network.

0:58Everything's connected these days.

0:59It kind of almost has to be.

1:01So this is what we're going to be taking a look at

1:03in this particular skill.

1:04We're going to be looking at IP version 4,

1:07addressing basics, okay?

1:09We're not going to delve all parts of it.

1:11We're not going to get into things

1:11like custom subnet masking,

1:13but we are going to look at the essentials of IP version 4.

1:17How do I identify what kind of an address it is?

1:20Whether it's a public or a private IP address,

1:22that sort of thing.

1:23We'll also be taking a look here

1:24at IP version 4 classful subnet masks,

1:28because you can actually use a subnet mask,

1:31which will identify in part what network

1:34a specific host belongs to.

1:37And properly subnetting will be pretty significant

1:40when it comes to making sure

1:42that something is set up properly

1:43and that you don't have troubleshooting

1:45further on down the road.

1:46Also look at IP version 6 addresses.

1:49Problem is IP version 4 addresses,

1:52well, there's really not as many

1:53as we thought there was going to be.

1:55And so we had to come up with some solutions.

1:56One of those is IP version 6.

1:58There's a substantially huge number

2:01of addresses available there.

2:03And IP version 4 private IP addresses,

2:06which is something we can use internally

2:08and not really be that concerned

2:10about running out of addresses.

2:11So those are some of the things

2:12we'll be primarily looking at in this particular skill

2:15as we get started in the world of networking.

0:00All right, let's get into it, shall we?

0:01So we're going to be taking a look here

0:03at IP addressing basics.

0:05First thing I want to point out here

0:06is that we're really focused on IP version 4

0:08for the majority of what we'll be discussing

0:10and what we configure.

0:11Reason for that is because internally in most organizations

0:15they're still using IP version 4.

0:17There is also an IP version 6,

0:19which uses a totally different scheme.

0:20The addresses look totally different.

0:22Everything's different.

0:23But internally, as we configure and manage networks

0:28and configure our networking services,

0:30generally speaking, we work with IP version 4.

0:34We'll get into more details about IP version 6

0:36a little bit later on,

0:37but just as we kind of scratch the surface with it, okay?

0:39Because again, we primarily do IP version 4.

0:41So first thing to understand is

0:44that you cannot just assign

0:45whatever IP address you feel like, okay?

0:47So on a single network, for example,

0:49I couldn't have one computer at 25.6.7.8,

0:55and then on another computer in that same network,

0:57I couldn't put it at 192.16.24.1, okay?

1:04Those hosts are unlikely to communicate with one another.

1:07So it has to be set up right, okay?

1:09One of the first parts of that

1:11is understanding the class of networks.

1:13There are three primary classes of networks,

1:16and then there's also a fourth one,

1:18which is not really used primarily in our discussion,

1:20but I'll get to it a little bit later on.

1:22So first thing let's understand is the class A network,

1:25all right?

1:25When you look at these addresses,

1:27and we'll get into some more of the details

1:29on kind of the mechanics

1:31of how all this works out mathematically,

1:33but when you look at this just visually,

1:35we're seeing decimal numbers here, right?

1:38So this is a decimal number.

1:39These are just kind of the numbers you see,

1:41one, two, three, four, five, six, seven, eight, nine,

1:43and so forth, that are human readable, okay?

1:45These are human readable numbers.

1:47Your computer will actually see numbers more like this,

1:50bunch of ones and zeros, okay?

1:52And it's really a string of 32 bits like that.

1:55Those are all bits.

1:56We're not gonna delve into that quite yet.

1:58I'm just gonna start with the human readable side of things,

2:02okay, that's easier to make out.

2:04So with a class A network,

2:06when you look at an IP address on a host,

2:08if it starts with any of these numbers,

2:10one up through 126,

2:13you could just eyeball that and immediately know

2:15that that's in a class A network, all right?

2:19Now, without muddying the waters too much,

2:21there are ways to cheat that.

2:23Just so you know in advance,

2:25in case you're thinking ahead of me

2:26and you're already familiar with networking,

2:28you can use a class A decimal network or a network ID

2:33or class A IP address,

2:35but you can kind of cheat it by using a class B

2:38or more likely a class C subnet mask, okay?

2:42So I'm just saying that right from the beginning,

2:43but we're gonna work with defaults right now.

2:46So yeah, this is the starting octet.

2:48These are all what we call octets, okay?

2:50Between the periods, okay?

2:52So that's the first octet is right here.

2:54Second octet is right here.

2:56Third octet right here.

2:58Fourth octet right there, okay?

3:00In this case, they're all the three remaining ones,

3:02they're all zeros.

3:03And again, we'll come back to octets

3:05and the meaning of that later on,

3:07but the significance of that is that there are eight bits,

3:10hence the term octet, O-C-T is Latin for eight.

3:14I don't know, I'm just saying that

3:15because I want it to sound like I went to college.

3:17Anyway, I actually think that's true,

3:19but those octets are all in binary bits

3:23of ones or zeros or whatever, okay?

3:26There's eight of them per octet.

3:28We'll look at that again in the next topic as we move on.

3:32But by default, and again, these are just the defaults,

3:34you can cheat this,

3:35but the default subnet mask would be a 255 here.

3:38So when you look at a network configuration, for example,

3:41you might have a host that has an IP address of,

3:44I don't know, 65.1.2.3, okay?

3:48That's its IP address.

3:49Let me write that down, okay?

3:51And it would have a subnet mask of 255.0.0.0, okay?

3:58So that would be how I would configure that.

4:01If I were using classful, this is also known as,

4:04I don't know if I have it on there, yeah.

4:05It's also known as classful subnet masking.

4:08In other words, using the default subnet mask.

4:10Now, here's another example

4:12of one of those IP addresses, right?

4:13It's a class A network.

4:15There's also, by the way, I should point this out,

4:17a 127 in here,

4:18which I'll talk about a little bit later on.

4:20Technically, that's also class A.

4:22It's just that it can't be used

4:23to communicate with any other host.

4:25So we kind of leave it out of this default class A network.

4:27But here's an example.

4:29I might have a host with an IP address of 109.210.27.4,

4:33right?

4:34It's gonna have, if we're using classful subnet masking,

4:37a subnet mask of 255.0.0.0.

4:40Now, I will point something out here, okay?

4:43With these bits, which again,

4:45that'll come to light a little bit more in the next topic.

4:47With those bits, we have a division here.

4:51So this means that wherever you see a 255 like that,

4:54or any number that's not zero, really,

4:57that identifies bits that are dedicated to the network, okay?

5:03So in other words, it creates a dividing line right there.

5:08Kind of messing it up,

5:09but creates a dividing line right there.

5:10I guess they're not equally aligned.

5:12So that would dedicate this to the host side, okay?

5:15And the subnet mask identifies

5:17which side belongs to the host.

5:20So there are eight bits there on the network side.

5:24And again, we're seeing this in decimal,

5:25so we don't see bits per se,

5:27but that'll come to light next.

5:29And then we have 24 bits,

5:30because there's eight bits in each octet.

5:32Eight times three is 24, right?

5:36So that means that I could have

5:38pretty much any other number I want

5:40through all of these ranges,

5:42for the most part, up to 255.

5:45So this could be at the maximum, for example,

5:47if I was on a 109 network, that could be 109 dot.

5:50And if I took the last available IP address

5:53in that whole range, it would be 255.255.254, okay?

6:02I don't want to get too confusing about that,

6:04but usually we do not use the last 255

6:08all the way to the end,

6:09because if it was 255 all the way through

6:14the end of that address,

6:14that would be what we call a broadcast address, okay?

6:17So we can't really use that for a specific host.

6:21All right, so what does this also mean, the 24 bits?

6:24Well, let's take a look at this in binary a little bit.

6:27And then again, I'm going to address that again

6:30on the next topic.

6:31But this means that how many networks could I have

6:35with an eight bit, 255 is what that is,

6:39with an eight bit subnet mask?

6:41Well, you have two possibilities in binary,

6:44there's a zero or a one.

6:45So there's two, and then to the power of eight equals,

6:50that means there are 256 possible

6:52class A networks out there.

6:55How about the host side?

6:56Because if you take a look at this,

6:57look, all the rest of these relate to the host.

7:01So that would be, you know, eight times three is 24.

7:04So let me clear the screen here.

7:06Two to the power of 24 equals 16,777,216 hosts

7:15that we could have on that network.

7:17Now, is that realistic?

7:19Not at all.

7:20You don't have 16 million ports in your data center,

7:24even a big data centers.

7:26I doubt if it's going to have 16 million ports

7:28that can even be plugged into.

7:30And I'm talking about ethernet ports

7:31on like a switch or something.

7:32So that's what I was saying earlier.

7:34A lot of times we'll cheat this

7:36and kind of break it up into what we call

7:38custom subnet masking.

7:39Okay, so anyway, just put that in your back pocket.

7:42We'll come back to it.

7:43How about class B?

7:44So class B subnet, excuse me, networks,

7:46class B networks will start with anywhere

7:48between 128 and 191.

7:52It will use a default subnet mask of 255.255.0.0, okay?

7:57Which you're going to divide it right in the middle here.

7:59Okay, so this one divided over here.

8:01This one shifts over an octet and it divides it right here.

8:05Here's just an example IP address

8:07because it's in this range.

8:08So 130.5.6.7, okay?

8:11And there would be its subnet mask.

8:13Now that's still probably not all that realistic, okay?

8:17Because let's go bring our calculator back over here

8:20to the power of 16, okay?

8:24Because we have two octets on the network side,

8:27two octets on the host side.

8:29So on the network side,

8:30we could have up to 65,000 networks

8:33that we could calculate there.

8:36And because it's split in the middle,

8:37we can also have potentially up to 65,536 hosts

8:42on the host side of things.

8:45Again, not a realistic number.

8:47Again, even in a big data center,

8:48you're still not likely to probably have 65,

8:51what'd I say, 65,000?

8:53Yeah, 65,536 addresses.

8:57So once again, you're probably going to kind of trick that.

9:00But nevertheless, that's the starting point.

9:03Unless you know the default classful subnet masks,

9:07you can't really customize it later on.

9:10You have to start with the classful side of things.

9:12All right, what's next?

9:13Class C, this is the most common one we'll use.

9:16It's the one I use in my own network here.

9:18And you'll very commonly see this in,

9:22gosh, anywhere, really.

9:23But it starts with anywhere between 192 and 223.0.0.0,

9:29or dot whatever is what all those zeros mean.

9:31And again, in this case,

9:32that would mean that the last possible usable address

9:35would likely be 223.255.255.

9:43Oops, my pen's doing weird things.

9:46Dot 254.

9:49That's likely the very last possible address

9:51you can use in that range.

9:54Here's an example of how that might look.

9:56223.64.32.16.

9:58Although, to be realistic,

10:00I probably should have put a different address in there

10:01because you're more likely to see

10:03in things like coffee shops, restaurants,

10:07possibly in hotels if it's not too big of a hotel,

10:10a home network, small office, home office.

10:12The most common addresses you're gonna see are 192.

10:16And by the way, if you're at home right now,

10:18you probably have an address that starts with 192.

10:20192.168, that's what it usually starts with.

10:23And then from here, a lot of times it'll go to dot one

10:27or sometimes dot 100, dot, and then whatever else.

10:31So these are the ones you see the most commonly.

10:34And this is the subnet mask they use,

10:36as I mentioned earlier, 255.255.255.0,

10:40also known as a 24-bit subnet mask.

10:43So this is a 24-bit subnet mask.

10:46Sometimes you'll see it with a slash notation like that.

10:48This is a 16-bit subnet mask.

10:50This is an eight-bit subnet mask.

10:53That's a slash, I'm not clear on that.

10:56So that's a lot of times how you'll see it as well.

10:58That's called a CIDR notation.

10:59Anyway, now what have we got?

11:01Well, every time we shift the network bits

11:05over to the right, so we started here,

11:07and then here we shifted over another octet.

11:10Here we shifted over another octet.

11:12Every time you shift over to the right,

11:14you lose host bits, right?

11:17But you will gain network bits.

11:20So this means that if we're gonna calculate,

11:22but that calculator is really huge.

11:23Let me shrink that down.

11:24It looks like a Fisher-Price calculator

11:26or something like that.

11:27Anyway, so let's go to, what do we got now?

11:30Oh, class C, okay.

11:31So I've got 24 bits.

11:34The math is gonna be the same here

11:36as what I showed you earlier, but 24 bits.

11:38So that's gonna be 24 to the power of,

11:40no, two to the power of 24, excuse me.

11:44And that would be the same number we saw earlier,

11:4616,777,216 possible networks we could work with.

11:52If we're using a class C default subnet mask,

11:58classical subnet mask, 255.255.255.

12:01How about the host side of things?

12:03Well, we're gonna have two to the power of this time,

12:06eight, because we only have eight bits

12:09on the host side of things.

12:10So two to the power of eight equals 256, okay?

12:15You might look at that and say,

12:16James, weren't you working with an address

12:19that ended in 254, and you said that was the maximum

12:22you could go, yes, but remember, zero is also a number.

12:24So that also counts.

12:26So zero through 255 equals 256 possibilities.

12:33Usually we do not use a zero

12:35with this classical subnet mask

12:38because this identifies the network ID, okay?

12:43Network ID.

12:44So if I were talking to another administrator

12:46and I would say,

12:47or maybe we're troubleshooting something, I'd say,

12:49okay, so what's your network ID over there?

12:52That person would tell me, she'd say 223.64.32.0.

13:01She'd say that was their network ID,

13:04and she'd probably put a 24 on the end of that

13:06to designate this kind of a subnet mask, okay?

13:09So this is not an IP address.

13:11This is simply telling me kind of the range,

13:13if you wanna put it that way,

13:14the range of network addresses that I'm using

13:17with that subnet mask.

13:18It's getting kind of messy, isn't it?

13:20All right, I'm gonna quickly go through the rest of this

13:23because I'm taking a little bit of too much time.

13:24So the loopback address, this right here,

13:27this is simply mostly a troubleshooting tool.

13:30It's going to be anything in this class A 127.0.0.0 range.

13:35Do you remember how many possible addresses that is?

13:38Yeah, 16,777,000 something addresses.

13:43And what is it used for?

13:45It is only used to ping your own network device.

13:50Okay, let me show you what I mean.

13:51So this is on my own computer right here.

13:53If I do a ping and use ping

13:56to see if something's kind of alive

13:58or can respond or whatever, it does not always work.

14:01Just FYI, and I'm getting ahead of myself a little bit,

14:04doesn't always work

14:05when you're trying to reach your actual destination,

14:07like something out on the internet,

14:09because certain network devices will block ping packets.

14:13All right, but inside the network here,

14:16and I'm just trying to see if I have basic IP functionality,

14:20I would do a ping 127.0.0.1, and I'm getting answers back.

14:25So what that tells me is at least in software,

14:27the operating system on my local computer,

14:30everything is pinging up and down through the stack,

14:32and that's working.

14:33This does not validate that the router

14:36that's in the server room 100 yards away is working.

14:40This does not validate that my switch is working.

14:43This does not validate that I can communicate

14:45with other hosts on the network.

14:47This only tells me that the basic functionality,

14:50it's kind of small, isn't it?

14:50Let me zoom in.

14:51It only tells me that the basic functionality

14:53for IP in software here in my operating system is functional.

14:59That's all that means.

15:00But that's what we use a loopback address for,

15:02is for that basic kind of testing.

15:04Now, the reality is, again,

15:06because we're using a class A subnet mask

15:08on a loopback address,

15:10we have all loopback addresses

15:12in this entire range right here, okay?

15:14So 16 million ways to ping yourself.

15:17So as a quick reference, also down here at the bottom,

15:19we've got these references for class A, B, and C,

15:24and then there's also this loopback address,

15:26which I'm covering up right now.

15:27Okay, so FYI, I will also put these down below for you,

15:32and they're gonna have a white background

15:33because if you wanted to print them out,

15:35it'll print out better with a white background

15:37than it will with this kind of dark themed background.

15:40Otherwise, the information should be the same,

15:42and I'll see you in the next video.

0:00Okay, so to be honest,

0:01one of the struggles that I had in the previous video,

0:04was to kind of switch back and forth

0:05between talking about what we call dotted decimal

0:08and binary and all of this kind of stuff, okay?

0:12Here, we're gonna kind of bring those two worlds together

0:14for a little bit of clarity here, okay?

0:16So again, we're working with a classful subnet mask,

0:19the defaults in other words.

0:20And again, with class A,

0:22remember we had an eight bit subnet mask,

0:24which can be in what we call CIDR notation, like that.

0:28CIDR notation would be a slash eight, a slash eight.

0:32And likewise for class B,

0:34the CIDR notation would be a slash 16,

0:36class C would be a slash 24.

0:38Those are all CIDR notations.

0:40When you have the network ID followed by a slash eight,

0:4416, 24, something like that, okay?

0:47Now, what does that mean?

0:48Well, the eight, the slash eight for example,

0:50means that it's using eight bits here

0:53as the network mask or the subnet mask, okay?

0:57So these are dedicated to the network.

0:59Anywhere you see a bunch of ones all strung together,

1:03that means network.

1:04Anytime you see all these zeros, that means the host side.

1:08So if someone shows me an IP address,

1:11it looks like this, I don't know, 32.5.6.1 forward slash eight

1:19that means that they're telling me

1:20they are on a class A default subnet mask, okay?

1:25So that's how that's used.

1:27Now, the decimal side of things,

1:28also known as dotted decimal,

1:30is really just for human readable format.

1:33Now, this is not really too hard to read.

1:35You can kind of make this out,

1:37a bunch of contiguous ones there.

1:38But nevertheless, one other thing I should point out there

1:42is that notice that they're all contiguous.

1:44In other words, it's not a subnet mask

1:47of one, zero, one, one, zero, one, one, zero,

1:50something like that, okay?

1:52It's mixing up zeros and ones like that.

1:54That doesn't work, all right?

1:56It's all contiguous ones, all contiguous zeros.

2:01There's not over here on the host side of things.

2:02There's not a zero, one, one, zero, one, one, zero, one

2:06or anything like that, all right?

2:07Again, all contiguous ones for the network side,

2:11all contiguous zeros for the host side.

2:14But again, for us weak-minded humans,

2:16it's just easier to read like this.

2:19Now, the reality also is, by the way,

2:22that your computer doesn't see this broken up

2:24with these divisions.

2:26Your computer just sees a continuous 32 bits total,

2:31all strung together.

2:32We divide it up to make it a little bit easier to read,

2:36all right?

2:37And likewise, over on the dotted decimal side of things,

2:39we even separate it with a period here,

2:42or a decimal really, the dotted decimals,

2:45we're calling that, so that we can break it up a little bit,

2:47make it a little more digestible

2:50in terms of putting eyes on it

2:51and seeing what we're working with.

2:52I mean, without it, we would have something like this,

2:54right?

2:55It's just, it's not as easy to identify

2:58what we're working with there.

2:59I mean, is that a 25.50.0.0?

3:03What is that?

3:04Or .0.0?

3:05Who knows?

3:06So that's why we put it in like this.

3:09So with deliberate action,

3:10we put in the dotted decimals there.

3:12Each one of these represents the binary side over here

3:16on the binary, right?

3:17So the 25.50.0.0 is a continuous string of ones

3:22in binary format.

3:24Now, it's really beyond my scope here

3:27to go into the math of that, but let me do it anyway,

3:30just to help make that a little bit more clear.

3:31And usually when I teach this in more depth,

3:34I write it all out and everything,

3:36but in this case, I'm just gonna cheat

3:37and use the calculator again.

3:38So for this one, I'm gonna change to the programmer version

3:41of the calculator here.

3:43And if I look at the decimal, if I click on decimal,

3:45I don't know if you can see that.

3:46Actually, maybe I should make this bigger now.

3:48Over here on decimal, that's what I've selected.

3:50You can see the little orange line next to it.

3:52If I click there, and with this, let me just put in,

3:55I don't know, any number, 192, let's say.

3:59Well, what does that equivocate to in binary?

4:02We can disregard for right now hex and octets

4:04and whatever that is, but in binary,

4:07that would be like this, right?

4:091100000, all right?

4:12Let's put another number in, 178, let's do that one.

4:17I'm just making a number up.

4:18With that one, the decimal is obviously 178,

4:22but in binary, that appears like this.

4:25Now, how do we make sense of that?

4:26So how would we convert that

4:28if we wanted to just do it mentally

4:29and not use the calculator here?

4:31Let me show you.

4:32I went ahead and pasted this in here

4:33to make it a little bit easier.

4:34What was our number, by the way?

4:35I just saw it, it was in the calculator, 178, okay.

4:38So how would I calculate that

4:39just doing that mentally here?

4:41Well, what I wanna do is to come up

4:43with some combination of all of these numbers

4:45that adds up to 178, okay?

4:48None of these numbers are bigger than 178,

4:50so I can start with the largest one, that would be a 128.

4:53And I can put a one or a zero here.

4:55Anytime I put a one in there,

4:57that means I will count that number.

4:59Anytime I put a zero in,

5:01that means I will disregard that number, okay?

5:04So if I had a one and a zero,

5:06that means I'll count the 128,

5:07but I will not count the 64.

5:10I think it will count the 32.

5:12You just gotta do the math in your head a little bit.

5:14Then I can add the 16.

5:15So what do we got here?

5:16128 plus 32 is 160, right?

5:21Yeah, and I'm trying to get to 178.

5:22So 160, this would give me 176.

5:27So I should only need two more to get to 178, right?

5:30That means I'll go a one there.

5:31That means the rest of these will be zeros.

5:33So what this is telling me is,

5:34anytime I see a one, I will count the number, okay?

5:38That is underneath it.

5:40So I'm counting up 128 plus 32

5:44plus 16 plus two equals 178, okay?

5:51So that's how we convert from binary to decimal, all right?

5:56Now we don't need to practice that a lot or anything.

5:58I'm just showing that right now

6:00so you can kind of get a comprehension

6:02for how we flip back and forth between the two numbers.

6:06Let's do another one just for a grins though.

6:08Let's just put the number.

6:10Actually, you can do this on your own too.

6:11Just pick a number out of the air

6:12and kind of use this little chart here to figure it out.

6:15Let's do 241, okay?

6:18So 241, I know I can use 128.

6:21I wanna use the larger numbers when possible.

6:23And by the way, there are no two ways to come up with this.

6:26Okay, there's only one combination that will work.

6:29So what did I just say?

6:31I can't remember what number I just said.

6:32Let's just go with 197, okay?

6:34So I'm gonna say, I'll write it down.

6:36197, all right?

6:39So 128 plus 64, I'm pretty sure that would give me 192,

6:46right, 192, yeah.

6:48So I'm not quite at 197 yet.

6:49What else do I need?

6:50192 and 197, the difference is five, so I need five more.

6:54So I need a four and a one, that's a total of five, right?

6:58So that would be like this.

7:00That means that the binary equivalent of 197

7:05would be 11000101, right?

7:11All of this right here, okay?

7:14So that's all I'm gonna do right there.

7:15We don't wanna get into that too much more depth right now.

7:18I just wanted you to see,

7:19besides just working with the Classful Subnet Masks,

7:22how I can use binary slash decimal conversions there

7:26using something like this

7:28to figure out what it would look like in binary.

7:31So the decimal is easy, right?

7:33It's a conversion into binary

7:35that we have to kind of twist our brains around

7:37and figure out how to use things like this, right?

7:40Anyway, you see the rest of the equivalents down here,

7:43and that's just there for your reference.

7:45Also, I should point out, there's also a Class D,

7:47we don't really talk about it much,

7:49and it's called multicasting.

7:51It's a multicasting range of addresses.

7:55The purpose of it is that I can send,

7:58you can see right here,

7:59one stream of data to multiple recipients simultaneously.

8:03So this can be used for like,

8:04maybe you have a LAN party,

8:06you know, a gaming, several people over

8:09and you're all playing games,

8:10we'll very likely be using some form of multicasting.

8:14This does not usually work on the internet, by the way,

8:16directly at least, maybe it would work,

8:18but I know that services like Zoom,

8:20they use their own thing, they don't use this.

8:22I don't think that Google Meet uses this either.

8:26There's not generally an internet thing.

8:28What else would use it?

8:29Apple TV, Roku,

8:31a lot of those kinds of things will do multicast.

8:33Another thing you could use it for, by the way,

8:35would be if I had a server here

8:37that was in a distribution server of some kind,

8:39we're issuing software from it,

8:42we're installing operating systems,

8:43then it can send a stream of data to three separate hosts,

8:48all at the same one,

8:49maybe it's transferring files to each of them,

8:52rather than sending a separate send to each host separately

8:57and consuming more network bandwidth,

8:59with multicasting,

9:01I can send the same stream of data simultaneously

9:03to all three of those.

9:04And of course that can scale up to a lot more than three,

9:06but that's the basic idea for how that works.

9:09All right, that's it.

9:11Classful subnet masking,

9:13and a little bit sprinkled in there

9:14of converting from decimal to binary.

0:00All right. Did you ever run into a situation where you ran low on something like money,

0:05for example? The other night, I decided to take my wife to a nice romantic dinner.

0:10I thought I was being quite nice. Anyway, took her to a nice romantic dinner,

0:13and I looked at the total of how much it was going to cost. It was $36. That's what I get for

0:21ordering two Big Macs and two hot fudge sundaes in combo meals. I can't remember what my wife ate,

0:28but that's what I ate. Anyway, it added up to more than I thought I was going to add up to.

0:32Well, the same thing has happened with IP addresses. The IP version 4 addresses that we

0:37have, well, there's about 4 billion of those addresses, but because of the way they were

0:42carved out and the way they were distributed and everything like that, let me show you,

0:46it turned out that all of the addresses got consumed. They were just wasted, really.

0:52They were not very efficiently divided up. That's because the IANA, which is the Internet Assigned

0:57Numbering Authority, it's an organization that divides up the addresses. They didn't realize how

1:01big the internet was going to get. Nobody really did. So I don't really blame them for that.

1:05But where did all the addresses go? I'll put this link down below so you can see this for yourself

1:09if you want. But this is where they all went. These are the class A address blocks that got

1:15distributed. Look, US military, the Department of Defense, which is now the Department of War,

1:20201 million addresses just for the Department of War. Now, that kind of makes sense in a way

1:27because DARPA was originally a military initiative and it was driven by military needs.

1:35And that's part of what all this is relating to. The internet was originally designed primarily as

1:40a redundant communications network for the military. So I guess that makes sense.

1:44Now, Department of Defense, they have 2.89 million employees, civilian and military.

1:51I don't even think that includes contractors. So yeah, they're a big organization. I think

1:56they're the biggest organization in the world, IT organization in the world. But you see a lot of

2:00other technical companies here and big companies like Hewlett Packard and Apple. And I think there's

2:06a car maker in here as well. Yeah, Ford. So you can see they've all got millions of addresses.

2:11MIT is in here. They've got 16 million addresses. But because of the way it was all divided up,

2:18they all got consumed much faster than anybody would have anticipated. And that's why

2:23we went to something called, or it is the RFC 1918. RFC is request for comments. And that's

2:30where you can kind of submit papers. You have to have some credibility like all of these brainiacs

2:34over here. And you can see there's people from Cisco and Chrysler and RIPE, which is a regional

2:40internet authority and stuff like that. Anyway, they came up with RFC 1918. And this allocates,

2:47where is it? Well, I just saw it. There it is, private addresses like this. So if you see

2:54addresses that start with any of these numbers, those are going to be the private IP addresses

2:59that you can use internally. They don't route on the internet. So you can't just put a 10 dot

3:05address directly on the internet. It won't go anywhere. The routers on the internet will just

3:09drop it immediately. There are ways around that, which I won't get into right now, primarily

3:14through NAT, which is Network Address Translation and or PAT, which is Port Address Translation.

3:19And most of the time we're actually using Port Address Translation. But when it comes to

3:23doling out addresses, one of the other things that they come up with is IP version six. This

3:29is to help guarantee that we don't run out of addresses in the future. And we're not going to

3:34touch on IPv6 much here because most organizations are still using IP version four, but I want you

3:39to be familiar with it. And again, I'm not going to read everything that's on this, but I will

3:43link it down below for your own reference. There are three main address types that you can use. One

3:47is Unicast right here. And this is kind of a overall type of an address type. Global Unicast

3:56right here is a subset of Unicast. And they also use prefixes just like we do in IP version four.

4:02But the main idea that I want to get to here is IP version six has substantially more addresses

4:09than we do in IP version four. In fact, it's 128-bit address. So let's take a look.

4:16With IP version four, we had two to the power of 32. And we can't use them all, but conceivably

4:22that's about 4 billion addresses, right? If we take a look at two to the power of IP version

4:27six addresses, which is 128 bits, that gives us whatever that is, which is actually, that's 340

4:35duo-decentillion addresses. Now I've heard that compared and expressed a number of ways. You can

4:41Google it or use some AI if you want to try to make a comparison. One of the comparisons I saw

4:47said that if you took every atom on the face of the earth times 10, that would be about 340

4:54duo-decentillion atoms. Okay. Wow. So that's going to take a lot. It's kind of hard to conceive that

5:02we would ever consume that many. But then again, people that say that have probably never seen my

5:08McDonald's bill. Okay. Anyway, that's kind of keeping an eye on the future. Now, most organizations

5:14will still use IP version four. That's why we've got this RFC 1918 that I was referencing a little

5:20while ago. So all I want you to know for now is if you just eyeball an IP address and it starts

5:26with one of these ranges, you can look at it and immediately say, without doing any math or

5:31calculations or anything, you can immediately say, oh, well, that's a RFC 1918. That's a private IP

5:36address is what we usually say. And we have class A, class B, and class C, and we have the same

5:41numbers here as we did in the address ranges I showed you earlier for IP version. So again,

5:47these are only usable for internal network use. So you'll see them in coffee shops,

5:52probably your own home, internet router has addresses that are being doled out

5:57in this address range. It might seem in hotels, unless it's a bigger hotel, it might be something

6:03different. But anyway, yeah, you will still see that. It'll still be an address if it's a bigger

6:07hotel with a lot of addresses that it needs. It might use something like this, because you're

6:12not going to have still 65,000 or a million addresses on a single network. You can have

6:17something like most organizations, like home routers and stuff will be 192.168.100 or 1.0.1.1.

6:28And that's usually a 24-bit subnet mask. Remember, 24-bit subnet mask means you're going to have

6:34about 254 usable addresses. So if you're in a bigger hotel, which needs more than 254 addresses,

6:41maybe they're going to be using something in the 172.16 address range instead, or they'll use

6:47multiple 192.168 addresses. So anyway, that's the basic idea there. But these are used internally,

6:53and they help us to expand and kind of almost indefinitely procrastinate our progression to

6:59moving into IP version 6, because once again, most organizations will still use IP version 4

7:05internally. The exception would be if someone wants, if an organization wants to transition

7:10to IP version 6, there's a lot of things there that could be used to transition to Rado. There's

7:16a dual stack where you'll have both. I can't remember if I showed you this. Let me clear

7:20the screen here and show you. IP config, all. And you can see here that in my, I've got more going

7:27on here than most people will have, because I have a lot of adapters installed. But anyway,

7:32there's an IPv6 address. You can tell that because it says IPv6 right there. But even if you didn't

7:37see that, you can just eyeball this and look at the length of that. It's a hex number. So in IP

7:42version 4, like I have right here and right here, notice it's only decimals. These are hex addresses

7:50which use letters in them as well. A through F could be used. You won't see a Z or a P or an R

7:57or something like that. A through F could also be in this. Anyway, just wanted to get an idea for

8:02when you eyeball an IP address, how you can kind of get a comprehension of what's going on with

8:08and what kind of an address it is.

0:00All right, let's go ahead and take a look

0:01at some of these validation questions

0:03and get an idea for what we've learned here, okay?

0:06First of all, with validation,

0:08what is the primary reason

0:10for the development of IP version six, okay?

0:13Let's just start at the bottom.

0:14How about to simplify the IP address structure

0:17for easier human readability?

0:20That's exactly what it is not, okay?

0:22It is not more readable.

0:24It's actually harder to read in most ways,

0:27but it does solve some problems

0:29that we come up against.

0:30And it's kind of a necessary evil,

0:32even though it's a little bit harder to read in some ways.

0:35To replace IPv4 due to its inefficiency in routing.

0:40No, that's not true either.

0:41We haven't really brought up routing,

0:42but IP version four does route pretty well.

0:44And there are a lot of different routing protocols

0:46that can route it just fine.

0:47Although IP version six

0:50has some additional innovations as well.

0:53But that's not the reason why we have IPv6.

0:55How about this one?

0:56Improved security features over IPv4.

0:59Actually, it is also more secure, I have to say that.

1:02We didn't discuss that though.

1:03That's not part of the material,

1:04but there are built-in security measures with IP version six

1:09that protect its traffic better than IP version four.

1:11Although again, since we didn't discuss it,

1:14that won't be a right answer for this.

1:15Here we can say to provide a larger address space than IPv4.

1:20Preventing future address exhaustion.

1:22At least in the foreseeable future, yes.

1:25It's a huge address space.

1:27All right, next one.

1:29What does a slash eight, for example,

1:31forward slash eight insider notation indicate

1:34about a subnet mask?

1:35Let's start at the bottom.

1:36It indicates a class C subnet mask.

1:38Well, do you remember what a class C subnet mask would be?

1:41255.255.255.0.

1:45Remember each one of those 255 represents an eight bit octet.

1:48So eight times three would be 24, okay?

1:52So that could not be the correct answer, okay?

1:55Unless it was asking for slash 24,

1:58then that would be right, but it's not, okay?

2:00How about this?

2:02Let's look for an eight here at the top.

2:03It uses eight bits for the host portion of the address.

2:07Hmm, sounds right initially because it says eight,

2:10but remember the forward slash eight

2:12refers to network bits, not host bits, okay?

2:16How about this?

2:17Indicates a class B subnet mask.

2:19No, you remember class B subnet masks are 255.255.

2:25Which in binary would be 16.

2:27So that'd be a forward slash 16 for that one.

2:31How about this?

2:32It uses 16 bits for the network portion of the address.

2:35Nope, that's exactly what that's not saying.

2:37That's saying it uses eight bits

2:39for the network portion of the address.

2:40So there we have it with that one.

2:42Which of the following IP address ranges

2:44could be used for class A networks, okay?

2:48First, let's start at the top here.

2:50128 to 191.255.0.0, hmm.

2:57Well, if you remember the range of IP address

3:00of IP version four class A addresses,

3:04that's not in that range, okay?

3:06I'll make this one simple.

3:07Remember it starts at one and it ends at 126.

3:12As a caveat to that,

3:13I can't remember if I mentioned the material or not.

3:15127 is a loopback address,

3:17is technically a class A address.

3:19It just can't communicate with any other system.

3:21So that's why we don't usually include it

3:23in that discussion.

3:24How about this one?

3:25192, whatever, to 223.255.255.0.

3:31Nope, again, that's not in the class A range.

3:34That would actually be a class C address range, okay?

3:38How about this one?

3:39224.0.0.0 to 239. all of that, okay?

3:44Well, remember that is actually

3:45our multicast address, class D, okay?

3:49So that leaves us with this one,

3:50which is also just the correct answer.

3:52One, whatever, through 126, whatever, okay?

3:56That would be the correct answer for that last one.

3:59And that concludes this particular skill.

4:01I'll see you in the next one.