CCNA Q & A: IP Adderss/Subnetting

Using a subnet mask of 255.255.255.224, which of the IP addresses below can you
assign to the hosts on this subnet. (Select all that apply)
A. 16.23.118.63
B. 87.45.16.159
C. 92.11.178.93
D. 134.178.18.56
E. 192.168.16.87
F. 217.168.166.192



Answer: C, D, E

Explanation:
Since the subnet mask is 255.255.255.224, the number of network hosts that is available
is 30. Every network boundary will be a multiple of 32. This means that every subnet
will be a multiple (0, 32, 64, 96, 128, 160, 192, 224) and the broadcast address for each
of these subnets will be one less this number (31, 63, 95, 127, 159, 191, 223). Therefore,
any IP address that does not end in one of these numbers will be a valid host IP address.
C. Valid Host in subnetwork 2 (92.11.178.64 to 92.11.178.95)
D. Valid Host in subnetwork 1 (134.178.18.32 to 134.178.18.63)
E. Valid Host in subnetwork 2 (192.168.16.64 to 192.168.16.95)
Incorrect Answers:

A. This will be the broadcast address for the 16.23.118.32/27 network.
B. This will be the broadcast address for the 87.45.16.128/27 network
F. This will be the network address for the 217.168.166.192/27 network