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class c IP ranges in CIDR notation

Victor Kimura
Victor Kimura used Ask the Experts™

Just wonder what is the CIDR notation for the class C IP range of, say: to

Well, I guess it would be to since I think the first and last are reserved, right?

Thank you,

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Director, Information Systems

The range has 256 IP addresses of which 254 are useable.
Dave BaldwinFixer of Problems
Most Valuable Expert 2014
Commented: to because there is and which are reserved.

it implies a shorter way to express the IP MASK
/24 means the number of consecutives 1s of the equivalent clas C IP MASK

/24  <=> <=>11111111.11111111.11111111.0
Qlemo"Batchelor", Developer and EE Topic Advisor
Top Expert 2015
Just to make it clear: The CIDR notation is another notation of the netmask, not the available IP addresses. So the answers with are correct. The usuable range is derived from the netmask, so it doesn't matter whether you note it as or /24, both allow for the same range and are interchangeable.

The usuable range is, as said correctly, the whole one minus the first ("all zeroes") and the last ("all ones") one. "all zeroes", which means all host bits are zero, which is the last byte in this case, is reserved for "the network", and "all ones" for the local (IP) broadcast address.
Victor KimuraSEO, Web Developer


Thank you for the explanations. It helps.