CISCO CCNA Exam – Q149

The network administrator needs to address seven LANs. RIP version 1 is the only routing protocol in use on the network and subnet 0 is not being used. What is the maximum number of usable IP addresses that can be supported on each LAN if the organization is using one class C address block?

A. 8
B. 6
C. 30
D. 32
E. 14
F. 16

Correct Answer: C

Explanation:
Since there is one class C network that means 256 total IP addresses. Since we need 7 LAN blocks and we cannot use the first one (subnet 0) we take 256/8=32 hosts.
However, since we need to reserve the network and broadcast addresses for each of these subnets, only 30 total IP addresses are usable.

CISCO CCNA Exam – Q99

You have been asked to come up with a subnet mask that will allow all three web servers to be on the same network while providing the maximum number of subnets. Which network address and subnet mask meet this requirement?

A. 192.168.252.0 255.255.255.252
B. 192.168.252.8 255.255.255.248
C. 192.168.252.8 255.255.255.252
D. 192.168.252.16 255.255.255.240
E.192.168.252.16 255.255.255.252

Correct Answer: B

Explanation:
A subnet mask of 255.255.255.248 will allow for up to 6 hosts to reside in this network. A subnet mask of 255.255.255.252 will allow for only 2 usable IP addresses, since we cannot use the network or broadcast address.