Subnet Design

1. An IP subnetting design effort is under way at a company. So far, the senior engineer has
decided to use Class B network 172.23.0.0. The design calls for 100 subnets, with the largest
subnet needing 500 hosts. Management requires that the design accommodate 50 percent
growth in the number of subnets and the size of the largest subnet. The requirements
also state that a single mask must be used throughout the Class B network. How many
masks meet the requirements?
a. 0
b. 1
c. 2
d. 3+
2. An IP subnetting design requires 200 subnets and 120 hosts/subnet for the largest subnets,
and requires that a single mask be used throughout the one private IP network that will be
used. The design also requires planning for 20 percent growth in the number of subnets and
number of hosts/subnet in the largest subnet. Which of the following answers lists a private
IP network and mask that, if chosen, would meet the requirements?
a. 10.0.0.0/25
b. 10.0.0.0/22
c. 172.16.0.0/23
d. 192.168.7.0/24

3. An engineer has planned to use Class B network 172.19.0.0 and a single subnet mask
throughout the network. The answers list the masks considered by the engineer. Choose
the mask that, among the answers, supplies the largest number of hosts per subnet, while
also supplying enough subnet bits to support 1000 subnets.
a. 255.255.255.0
b. /26
c. 255.255.252.0
d. /28
4. A subnet design uses Class A network 10.0.0.0, and the engineer must choose a single
mask to use throughout the network. The design requires 1000 subnets, with the largest
subnet needing 200 hosts. Which of the following masks meets the requirements and also
maximizes the number of subnets?
a. /18
b. /20
c. /22
d. /24
5. An engineer has calculated the list of subnet IDs, in consecutive order, for network
172.30.0.0/22, assuming that the /22 mask is used throughout the network. Which of the
following are true? (Choose two answers.)
a. Any two consecutive subnet IDs differ by a value of 22 in the third octet.
b. Any two consecutive subnet IDs differ by a value of 16 in the fourth octet.
c. The list contains 64 subnet IDs.
d. The last subnet ID is 172.30.252.0.
6. Which of the following are valid subnet IDs for network 192.168.9.0, using mask /29,
assuming that mask /29 is used throughout the network?
a. 192.168.9.144
b. 192.168.9.58
c. 192.168.9.242
d. 192.168.9.9
7. Which of the following is not a valid subnet ID for network 172.19.0.0, using
mask /24, assuming that mask /24 is used throughout the network?
a. 172.19.0.0
b. 172.19.1.0
c. 172.19.255.0
d. 172.19.0.16

8. Which of the following is not a valid subnet ID for network 10.0.0.0, using mask /25,
assuming that this mask is used throughout the network?
a. 10.0.0.0
b. 10.255.255.0
c. 10.255.127.128
d. 10.1.1.192