Your network design calls for 17 subnets supporting 35 hosts

Your network design calls for 17 subnets supporting 35 hosts each. Your company provides the 135.72.0.0 address space. Which subnet mask would you create to satisfy the requirement?

A. 255.255.252.0

B. 255.255.254.0

C. 255.255.248.0

D. 255.255.240.0

Solution

B and D are correct. 255.255.0.0 is the default subnet mask for a Class B address space, and 255.255.254.0 is a valid subnet mask.

A, C, and E are incorrect. A is not correct because 255.254.0.0 will not work because it is smaller than the default mask for a Class B address. C is not correct because 255.255.245.0 will not work because 245 is not allowed (it is not a consecutive series of 1s) within a subnet mask. E is not correct because 255.255.192.224 is incorrect because the subnet mask must always be a series of consecutive 1s from left to right.