## Subnet mask calculation

5 pts.
Tags:
Microsoft Windows XP
Subnets
Which host are in the subnet mask 172.16.16.0/20 and how do you confirm this to be applicable in other examples? 172.16.16.1/20 172.16.18.5/20 172.16.31.254/20 172.16.24.0/20

Software/Hardware used:
windows xp,vista,7

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My previous answer is wrong.
/20 subnets increment is by 16, not by 6 as I stated before.
Therefore, all addresses in your question reside in the same subnet.

P.S.: How can I edit my previous post and putting in it, strikeout text?

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Hello TB3,

Although when you already are proficient in sub-netting, explaining it here in a meaningful way is not that easy.
It takes some math and most of all practice…

172.16.16.1/20
172.16.18.5/20

These two addresses are in the same subnet of 172.16.16.0/20.
Because the subnet mask is /20, every subnet increases in 6. So, being 16 (3rd octet) the first subnet, the next one will be 172.16.22.0/20.

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If you work the subnet bits you find this:

172.16.1111 0000.0000 0000 (the Class B /16 +4 = /20)
– subnet 1: 172.16.0.0 – 172.16.15.255 (hosts 0.1 – 15.254)
-<b> subnet 2: 172.16.16.0 – 172.16.31.255 (hosts 16.1 – 31.254) </b>
– Subnet 3: 172.16.32.0 – 172.16.47.255 (hosts 32.1 – 47.254)
— etc —

So – to answer your question, ALL of the Listed IP addresses are in the same subnet

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