# subnetting again? pls help

Member Posts: 21 ■□□□□□□□□□
Hi,

After studying subnetting through CBT nuggets and with this forum I am feeling quite comfortable with it. But there are some questions I can't really understand..

By now I know how to subnet, subnet based on hosts and how to find valid range.

But while practicing at subnettingquestions.com. I can't answer few questions and luckily all the questions are of same time.

I also tried to find the answer using the calculator but I think i dont know what to look for

please have a look on the above problem and let me know what you guys think::::

• Member Posts: 73 ■■□□□□□□□□
You either found a bug or need to reset and try again

128 64 32 16 8 4 2 1
172 1 0 1 0 1 0 0 0
22 0 0 0 1 0 1 1 0
224 1 1 1 0 0 0 0 0
107 0 1 1 0 1 0 1 1

10101000 00010110 11100000 01101011
11111111 11111111 11110000 00000000

Line up the bits that match giving you
Host IP = 172.22.224.0

ALso if you want a double check site try this

Online IP Subnet Calculator

good luck
• Member Posts: 149
take 172.22.224.107 put mask under it

172.22.224.107
255.255.240.0
______________

1) if mask is 255 enter the number if make is 0 enter 0

172.22.224.107
255.255.240.0
172.22.____ .0

take 256-240=16

keep add 16 till you reach what would be in the missing octet.

16
32

64

192
208
224
240
256

224 is there on the money

so its in subnet 172.22.224.0

Now if it was 172.22.220.107 255.255.240.0

the subnet would 172.22.208.0

the valid range is 172.22.208.1-> 172.22.223.254

got it.
:thumbup:

Phil 4:6 "Be careful for nothing; but in every thing by prayer and supplication with thanksgiving let your requests be made known unto God."
• Member Posts: 3 ■□□□□□□□□□
255.255.240.0 is different that 255.255.255.240...

255.255.240.0 = 11111111.11111111.11110000.00000000 = /20

255.255.255.240 = 11111111.11111111.11111111.11110000 =/28

172.22.224.107/20 subnet range 172.22.224.0-172.22.239.255

I would recommend that you do not use a calculator. Do it manually and it will click.

use this site for practice -> subnettingquestions.com - Free Subnetting Questions and Answers Randomly Generated Online
• Member Posts: 21 ■□□□□□□□□□
damm.. i got the subnet mask wrong and i was so confused. thank u all so much