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I have an Ipv4 180.3.0.0 (class B, network bits reserved - 16bits). What are my possible subnet masks if i want my network to have at least 22 subnets and 120 maximum hosts?

I can understand that i need to give 5 bits for 22 subnets and 7 bits for 126 usable hosts but i can't undestand how when the question ask a minimum 22 subnets and a maximum 120 hosts each subnet.

What i tried so far is i tried to give certain bits to the subnet part and the others to hosts part, creating a range of possibilities but i don't see how that solves my problem.

Anyone can help me understand the logic behind this?

Demokles
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    Network address classes are dead (please let them rest in peace), killed in 1993 (two years _before_ the commercial Internet in 1995) by RFCs 1517, 1518, and 1519, which defined CIDR/ We have not had network address classes in this century. [This two-part answer](https://networkengineering.stackexchange.com/a/53994/8499) explains exactly how to subnet. – Ron Maupin Jan 04 '22 at 22:18

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As I see it, the "at least" and "maximum" constraints indicate the priority of the values: the 120 maximum hosts carries a bit more weight as it dictates the size of mask you will need to use even after you've satisfied the number of subnets constraint. With a /16 network it would be easy to subnet it to provide more than enough large networks. For example, you could subnet it to a /24 and get 256 subnets (which is fine given the at least 22 networks condition) each with 254 host addresses. However, this fails the maximum 120 hosts constraint. So to satisfy the scenario you must select a mask that still provides many more subnets than required but that are each smaller in size (less than 120 hosts).

mu_Lah
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