### Create a Subnet

Course
Time
1 hour 19 minutes
Difficulty
Beginner
CEU/CPE
2

### Video Transcription

00:02
Hello. Welcome back to cyber is create a sub net. Today we'll be going over the I P before class full networks.
00:08
That would be your instructor, Trenton. Jiro. Let's go ahead and get it.
00:12
Are so today we're gonna look at the different classes of I P before networks specifically looking at RFC 7 91
00:19
we're gonna jump right in with the class A network that is gonna have an I p. Range of one day 0001 26 to 35 to divide 2 55
00:31
And the way that these air set here you're going to see is well, first, we'll just go over the things, right, So So you get sub net mask. That's gonna be just just to 35 right
00:42
when cider slash eight.
00:45
So whether these work and the way that they're designed was you look at the first bit that is, in a classic network, it's always gonna be a zero, Right? Because you do 0111 Let's just do the max number, eh?
00:58
C four.
01:00
So seven. Right. So this is gonna be was counted out. 64 32
01:07
16 8
01:10
4 to 1 right, that's gonna equal 1 27 You say, Wait a minute.
01:17
1 27 is about 1 26 You'd be right. That is a reserved network that they have pushed out through the our seas. To say, Hey, this is for local host use only because a lot of times you'll see the jokes that say there's no place like 1 27 00 that one right, because that's your local host address that you could get your computer's going to use.
01:38
So you're hosting like a Web server for, say, you could type in local host dot com. You could take in a 1 27 0001 and it will bring up the same thing, right in a way. So we look at the total number of networks here. We have 126 networks, which looks kind of obvious because we go from 1 to 1 26
01:56
But the math on that is too raised to seven minus two. We do mine. It's too, because we don't use the 00001 as you might expect, and we don't use the 1 27 right, so we got a minus two networks off that there was technically, by binaries we use we have 100 and 28 right?
02:15
But then we have a total of almost 17 million hosts for sub net. And you might think, Trent, that's a lot of wasteful way only have 50 devices. Why would we possibly need 16 million addresses?
02:29
Yeah, you're probably right. And you're gonna say that could cause a massive broadcast storm when everybody and 16 million addresses is trying to our beach other. They're all trying to get that our message, right? That's a lot of broadcast. That's a lot of wasted I p space.
02:44
Ah, but don't worry. We minus two for the sub nets, the network I D and the broadcast address. You're going to see that in every sub net. You always minus two for that network idea than the broadcast address.
02:57
But here is a perfect example of why we could break up a you know, 10 dot network. If you're using a RFC 1918 address being up one of those private I P addresses, right, you might see a 10.0 slash 24. Right? That's submitting that. Submitting that that's class a address. In a simplest form.
03:16
Right now, you only have 254 addresses for I P for devices. Right?
03:23
And you have You know, how many more networks that you can actually utilize
03:28
without wasting all that eyepiece space. Right,
03:31
So we're gonna go ahead and move on to a Class B network
03:36
on there. We go to your class B range. We're looking at 1 28 to 1 91 to 35. 35 to 45. Right.
03:44
And here you're if you notice we're on a cider slash 16 compared to a slash ate last time. Which means our sudden that mask would be to 55 2500 Right. Ah, you'll see that the 172
04:00
16 through 31
04:03
private eye piece spaces here in this one. And here, the 1st 2 bits is set to 10
04:11
Right.
04:12
So we looked at 10111 See? It's 678 right?
04:18
Yeah.
04:19
So this would equal what we got. 1 28
04:25
plus 30 to 16. +84 to 1. So that equals what,
04:33
right? Hopefully you got that will equal. You're 1 91 Right,
04:39
which, if you notice, does coincide with this one here in this time, right? And then these Well, this would be the very max space. This isn't necessarily your i p space this. Ah, the 1 91 to 55 would be your actual largest class ful class B network. Right?
04:59
This 2 35 to 35 would be your largest i p address. But again, that last i p address is broadcast address. He couldn't actually utilize that one.
05:08
So here again, we look at total networks to raise a 14.
05:14
Right? So it leaves us with 16,000 networks that we can possibly using a class B, uh,
05:20
network or the class B range. That leaves us with about 65,000 hosts for sub net. Again, you might ask Trent, That's pretty wasteful. I might only have 5000 address. That's why do I possibly need 65,000
05:36
again? This is why we sub net again. You could do a slash 24 give yourself 254 usable addresses with how many more? Ah, different sub nets. Right and again, You minus two for the network. I D and that broadcast address.
05:53
So it's going to clear the screen and move on to the Class C network.
06:00
All right, so here we have the 1 92 000 through the 2 33 to 45 to 35 to 35. Right.
06:08
And here, the 1st 3 bets are 110 that would you. 121234 Right. So here, 1 28
06:18
plus 64 we are gonna avoid that. 32
06:23
16 8
06:26
for 21 gives us what, 2 30 to 23 which
06:32
does match up with this one. And here you're.
06:36
This would be your largest network here.
06:40
06:46
And, of course, we have a sudden a mascot to beautify it. Identified 2 55 0 on a cider mask of slash 24.
06:55
This one you'll see quite often. And home networks, because it's pretty. It's not very often that you're gonna have more than 254
07:02
Ah, peas and home network. So it's not really like your mess there. You're not. Ah, you know, not utilizing the space, so
07:11
it doesn't hurt any here. We have just about two million class C networks, right to quite a few,
07:17
but we only had 256 hosts for sub net. And of course, we minus two for not idea and broadcast. So again, that leaves with 254 usable I p's for each class cease class, full network,
07:32
it's a mouthful.
07:34
All right, so let's go ahead and move on to the class D and class E addresses, so these we don't generally use, right? You're going to see this as pretty much utilized for multi cast.
07:49
Uh, you see these a lot and some D o D networks. Um, you'll see a lot of multicast address, and here
07:59
we kind of just fouled the same type of bit pattern. Or start with 1110 And then, you know, if you continue that with the 1111 at the very end with the last four bits,
08:09
this is gonna be your last usable,
08:11
uh, sub net. Right.
08:15
So you received for multi cast quite often
08:18
and the class E is utilized for experimental usage. They're not utilized much outside of that, right? You can use them just
08:26
out of experiments, right? It's not going to be publicly rideable from your host. Something right? I shouldn't be.
08:33
Just go out and clear it, and we're gonna move on to the quiz for today.
08:39
So, see if you can remember this year how many usable hosts are in a Class B network? Give you a few seconds pause video.
08:50
All right, Hopefully you got this one. Remember? There is a total number of this money I p's in a Class B network, but we need to minus two off of that
09:01
for usable hosts. Remember, we have the 1st 1 That's our network. I d. On the 2nd 1 That's our broadcast idea that we had to get rid off,
09:09
but it is a quick little review of I p four networks. We're gonna go ahead and move into sub knitting and module to so I hope you'll join me. And thank you for watching the video

### Create a Subnet

This course will enable students to refresh on basic IPv4 and IPv6 concepts and to learn how to subnet an IP space in order to better provide network availability. We will dive into converting decimals to both binary and hexadecimal.

### Instructed By

Trenton Darrow
Network Engineer at NCI Information Systems, Inc
Instructor