Cisco CCNA mock exam questions sample test – Question 157

.You have been assigned a network ID of 172.16.0.0/26. If you utilize the first network resulting from this ID, what would be the last legitimate host address in this subnet?

A. 172.16.0.64
B. 172.16.0.63
C. 172.16.0.62
D. 172.16.0.65

Correct Answer: C

Explanation:
When a class B address such as 172.16.0.0 is subnetted with a /26 mask, the subnet mask in dotted decimal format is 255.255.255.192. This means that the interval between the
network IDs of the resulting subnets is 64. The resulting network IDs are as follows:
172.16.0.0
172.16.0.64
172.16.0.128
172.16.0.192
172.16.1.0
and so on.
For the network ID 172.16.0.0, the last address in the range is 172.16.0.63, which is the broadcast address. Neither the network ID nor the broadcast address for any subnet can be
assigned to computers. This means that the addresses that can actually be assigned range from 172.16.0.1 to 172.16.0.62. The last legitimate host address, therefore, is 172.16.0.62.
172.16.0.63 cannot be used because it is the broadcast address for the 172.16.0.0 network.
172.16.0.64 is the network ID for the 172.16.0.64 network, and 172.16.0.65 is the first address in the second network.
Objective:
Network Fundamentals
Sub-Objective:
Apply troubleshooting methodologies to resolve problems
References:
Cisco > Support > IP Routing > Design TechNotes > Document ID: 13788 > IP Addressing and Subnetting for New Users