Cisco CCNA mock exam questions sample test – Question 365

.What is the broadcast address for subnet 172.25.4.0/23?

A. 172.25.4.255
B. 172.25.5.255
C. 172.25.6.255
D. 172.25.7.255


Correct Answer: B

Explanation:
The broadcast address for subnet 172.25.4.0/23 will be 172.25.5.255.
When using a mask of /23, the subnet mask is 255.255.254.0. This means that the interval, or block size, of each subnet is 2, and that it will be incremented in the third octet.
Therefore, the next network ID after 172.25.4.0 will be 172.25.6.0. Since the broadcast address of each subnet is the last address in that subnet before the next network ID, the
broadcast address will be 172.25.5.255.
172.25.4.255 is a valid address in the 172.25.4.0/23 network, since the network range is 172.25.4.1 – 172.25.5.254.
172.25.6.255 is a valid address in the 172.25.6.0/23 network. Its range is 172.25.6.1 -172.25.7.254. Since the next network ID after 172.25.6.0 is 172.25.8.0, as the interval is 2 and it
is incremented in the third octet, the broadcast address would be 172.25.7.255.
For the same reason, 172.25.6.255 is the broadcast address for the 172.25.6.0/24 network.
Objective:
Network Fundamentals
Sub-Objective:
Apply troubleshooting methodologies to resolve problems
References:
Cisco > Design Tech Notes > IP Routing > IP Addressing and Subnetting for New Users > Understanding IP Addresses > Document ID: 13788