# Subnetting Knowledge.

Member Posts: 239 ■□□□□□□□□□
hey guys

so I've been having a crack at subnetting for the past 3 years and I finally get it Well i think so i know it took me 3 years i feel stupid lol but anyway I just have a question if I know how to do the following:

figuring out Valid Host Ranges
figuring out How Many Hosts per Subnet

what percentage of subnetting do I know?

• Member Posts: 1,740 ■■■■□□□□□□
Am I right in thinking that you said that you have figured out subnetting, but then you asked how do you do the following - which is subnetting. So, do you get subnetting or not?

In my experience for subnetting you do the following.

The company would like 10.10.70.0 as their IP. They need 5 networks.

5 in binary = 00000101, which is 3 bits (even though it's only 2 bits, you count from the left).

Add the 3 bits to the subnet 255.255.255.? the last octet you'll add the 3 bits, which will be 11100000. Which is 224.

The subnet will be 255.255.255.244.

You then calculate the ranges which will be in the range of 32. You count the range from the 3 bits that you used, which is, 128, 64 32.
There you will get your range. 10.10.70.1 - 32 (but you can't use the first or last) so it'll be 10.10.70.1 - 10.10.70.31 and so on.
2017 Certification Goals:
CCNP R/S
• Member Posts: 239 ■□□□□□□□□□
sorry if that was abit confusing what I meant was I know how to do the following:

figuring the Valid Host Ranges
figuring the How Many Hosts per Subnet

what I'm trying to say is If I know how do those what percentage of subnetting do I know ?
• Member Posts: 586 ■■■□□□□□□□
Hi,
There;s many different ways to subnet. I personally stuck with the method shown in the sybex net+ book. I think there is a dedicated sticky on the topic of subnetting here on this forum
I'm an Xpert at nothing apart from remembering useless information that nobody else cares about.
• Member Posts: 239 ■□□□□□□□□□
ok so I came across this question on subnettingquestions.com I understand the basics I dont understand this question if anyone could explain on how to solve it I would appreciate it.

You are designing a subnet mask for the 192.168.98.0 network. You want 50 subnets with up to 2 hosts on each subnet. What subnet mask should you use?

Thanks.
• Member Posts: 661 ■■■■□□□□□□
I would suggest CBTNUGGETS. Jeremy helped me tremendously with subnetting. His method is the best I've used. His method(s) also are the quickest which helps for exam purposes. Good luck.
• Member Posts: 1,740 ■■■■□□□□□□
sina2011 wrote: »
ok so I came across this question on subnettingquestions.com I understand the basics I dont understand this question if anyone could explain on how to solve it I would appreciate it.

You are designing a subnet mask for the 192.168.98.0 network. You want 50 subnets with up to 2 hosts on each subnet. What subnet mask should you use?
Thanks.
255.255.255.252 - hopefully I didn't just give you the answer for your homework.
2017 Certification Goals:
CCNP R/S
• Member Posts: 556
sina2011 wrote: »
ok so I came across this question on subnettingquestions.com I understand the basics I dont understand this question if anyone could explain on how to solve it I would appreciate it.

You are designing a subnet mask for the 192.168.98.0 network. You want 50 subnets with up to 2 hosts on each subnet. What subnet mask should you use?

Thanks.

So the requirements are 50 subnets, with 2 hosts on each. You need to find out how many network bits you're going to "borrow" to subnet the 192.168.98.0 network into 50 subnets.

192.168.98.0 is a class C network, so you're going to start subnetting in the 4th octet. To find out the number of network bits you need, you can either do 2^n, where n is the # of bits you'll need. So in your example, if you only borrow 5 subnet bits, you'll get 32 subnets (2^5 = 32). So, you'll need to borrow 6 network bits to satisfy the 50 subnet requirements. 2^6 = 64. This means that your mask will be 11111111 11111111 11111111 11111100 or 255.255.255.252. This leaves you with 2 hosts bit, which gives you 4 address per subnet (2^2 = 4). However, only 2 are usable becuase 1 is the network address and the other is the broadcast address.
• Member Posts: 239 ■□□□□□□□□□
hey pham

thanks for the great explanation I got it now.

Cheers.
• Member Posts: 239 ■□□□□□□□□□
I was just doing some questions on subnettingquestion.com

and I found a werid one that I never came across i got everything right exept the last part well here the question:

What valid host range is the IP address 172.16.213.169/22 a part of? Answer: 172.16.212.1 through to 172.16.215.254

I got the 172.16.212.1 correct but I got 172.16.215.254 wrong.

my answer was 172.16.212.254 so im going doing something wrong in the 3rd octect can anyone give me any hints.

thanks.