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I apologize if this is a too simple question for the people here, but this is my problem:

I am tasked to determine the subnetmask (binary), subnet mask (decimal) and the Prefix notation for a set amount of hosts. All I have is the number of hosts.

Can anyone explain how I go about determining this for for example 75 hosts? I don't know how to start and hours of googling has gotten me nowhere.

edit: this is different from other similar posts because I don't have anything other to go from than the number of hosts.

CUPA
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1 Answers1

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if your subnet needs to be as big a net for 75 hosts you cleary need a single /25 subnet.

How do I know that?
The answer is quite simple:
Within a /24 net you can store 255 IP adresses minus 2 adresses for host- and broadcast adresses which are the first and the last adress in your adress space.
Within a /25 net you can store half (128) of the amout of a /24 net (minus 2 adresses = 126).
Within a /26 net you can store a quarter (64) of a /24 net and a half of a /25 net (minus 2 adresses = 62).
So basically a /26 doesn't fit your needs because it's too small.

Furthermore you should read Cown's linked answer which might help you: https://networkengineering.stackexchange.com/a/53994

Best regards.

mushr00mer1990
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