Why Welcome back, everyone. Now, we're getting there, you know, you know what an IP address looks like? You saw that there's special addresses, but there's also classes of IP addresses. Yes. In ipv4, there are classes of IP addresses. Don't tell me there's no more classes of IP addresses.

No, there Yeah. And ipv6, there is no classes. ipv4 there still classes. So you're asked again on a certification, or even an interview, they may even ask you this. Well, what client know what class of addresses that just because they want to be smart about it. While you're so just look at the first talk, they will tell you, okay, and that's what I'm trying to say.

When classifying an IP address, you will look at the first octet. That's how you classify an IP address. Look at the first octet. I will tell you with an A, A, B, A, C, A, D or E. Okay? Well we're going to do is we're going to go inside, so you can see nice and clear and nice and neat by all the classes from A to E, okay? their range in the first octet, why to make them that particular class of address and their default mask and how many holes they hold using a default mask.

Okay, so let's go inside the lab and get that done. see you inside, walk on everyone, to the classes on IRS lab. All right, just so you can see this a lot better, less. Matter of fact, I'm gonna make this a little bit bigger than what it is now. So you can see it. There we go much better.

All right now here we go in our class all the classes that exist a B CMD ABCD Any e we don't use his left for experimental reasons, but let's leave out the range. Vi is multicast. ABC is really the ones that we use. Well, let's take a look at what I remember here we're looking when I put the numbers up there, those numbers belong to the first octet. So let's go here is going to be one through 126. All right, why one through 126 because zero is reserved and 127 is reserved, remember, so that's why they don't show up in this range.

Now, their default mask or cider or ddn will be a cider eight, or a ddn of 255000 and the default number of hosts using the default mask would be 16,777,240 that would be the default number of hosts. Okay using the default math. Now for B will always be 126 we can use 127. So 128 will be the next starting point, and then it will go all the way up to 191. Okay, here though in a class B, our slider will be a 16, meaning the first two octets are fully on, so we cannot mess with that for now. 255 that's three by 500.

That will be the ddn or dotted decimal numbering, fine, or dotted decimal notation. They don't change up the acronyms all the time, and then the default number of hosts 65,536 Okay. And then we'll see we are 192 through whoops, on for an IP address one through 223 spaces correctly so everything can be hunky dory. As for back, this was okay, cool. Back over here. All right, awesome.

So now the default mask here would be a 24 or Insider. spread this out underneath there you go. Okay, or the dotted decimal will be 255-255-2550 with exactly 254 IP addresses for fuse. Now the Class D multicast address range. Remember, we're looking at the first octet. These numbers you see there in the range are numbers that would show up in the first octet, okay.

So you can classify the address accordingly a 234 dash 239, but they do not have a default mask or host range, right because it says there's specialized IP addresses. Okay, use for a specific purpose, such as the routers, user 234, you know, the 009005, or six or the 00 10. I for their updates between routers. So those are specialized addresses or performing web conferencing and you want to only allow certain people within a multicast group you can use this type of address. I'll put it here on the side I'll call it multicast addresses Okay. And then the last one, which is known only by experimental is 240 through 255, right the last maximum value of any given octet, and a and they, and they call it experimental.

I call it block size. Right? Meaning that, hey, we can use this for whatever reason. So you can see why ipv4 didn't and finally got to a point where it's like, Hey, I'm bulging out the bridges. I'm not going to be able to do you know, I can't handle the amount of load that exists online publicly and privately when we talk about public and private addresses. is just way too many way too many devices on the network for just 4.2 billion addresses.

Sounds funny, but it's true. And that's why ipv6 came about and why that's why a lot of devices or protocols were in place to allow us to continue to use ipv4 such as Nat. Okay, that's a big thing the other Sherm, or this they're all devices that were put on there so we can go ahead and continue to use ipv4 but there you go. These are our classes are the addresses arranged their ciders and their default holes range, I will see you outside the lab and we're back in the real world. So you saw that it wasn't difficult to organize it for you here in a little table. All right, which you will have access to this is we have those abs CD, you saw it in there.

And this is just your first octet. Okay, one through 126. If you look at an IP address and you notice that it's one through 126, or Hey, that is a Class A address, it was 122 91 was a Class B one a two to 23 Class A Class D to 24 to 39. Just like but what do we say about 224? These are more Instituto nine. Those are multicast addresses.

Remember, we did Oh 22400 922-400-1022 4005 or six right for the routing protocols. And then he who? The Black Ops, you can use it at all right, mysterious, nobody tells us what is this this is experimental. Okay. And obviously you have a sider notation, y which means a bit wrong. 16 bit wrong.

24 Bits wrong. And you have these are the default math meaning when you type in, all right, I told you this already, but I want to reiterate it When you type it in into your PC listing, and you hit tab, there's going to put the default mask based on the first octet, that what number you put in there, but then you put whatever mask you actually need. And here we have the actual numbers, or using the default mass number host, they're allowed. Again, when this is going to go into the design aspect of it later on, if you know that your company is going to grow, you know, you have you may have many networks and in class C, okay, but you may run out so be careful. So you usually schools or glamorization use a Class B or Class A. So they don't have to worry about running out because they need to add more printers, more phones, more PCs, whatever the case may be.

They don't have a problem or running out of IP addresses. And now with ipv6, you know, quintillion per network. Id you know, we don't we don't have to worry about it. Okay, so this is it. And remember we are looking at the first octet and octet only. Remember what I stayed it was the 127 as your loopback Okay, that's your loopback so that's not gonna be there.

Why is the zero there because it's reserved as well. We talked about that. So again, they may ask you this but they asked you this they're gonna ask you this and on a plus network plus Yes, believe it or not a plus or network plus exam. A they go insane. They may ask you in the Cisco maybe, maybe, I mean now a long time ago, you know, bet rock days, they will go ahead and pull questions like this, but you need to know because you're gonna go to an interview and you want to know all these you know basics what you're looking at, and you know, what you could be working with and stuff like that. So this is something basics that everybody should know.

There's like your alphabet, the you know, okay Is there a B is that whatever, you should know it, you should know it. Because again, interviewers love to Ask questions. Okay. And you may be the person that gets asked a silly question like this, and you need to answer. Okay, so there you go. Those are your classes of IP addresses.

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