A network engineer is subnetting the 10.0.240.0/20 network into smaller subnets. Each new subnet will contain between a minimum of 20 hosts and a maximum of 30 hosts. Which subnet mask will meet these requirements?

a. 255.255.224.0

b. 255.255.240.0

c. 255.255.255.224

d. 255.255.255.240

Answer:255.255.255.224

Explanation:

/20 has a subnet mask of 255.255.240.0

We have 20 on bits for the network and 16 off bits for the host. Since the designer wants 20 to 30 hosts in each subnet we will be having 5 off bits for the host. Therefore we will be having a / 27 ...

Which will be 255.255.255.224