Question for students: What is the subnet address for the following host: 192.168.16.17/28?
Answer: 192.168.16.16
Working: The 28 signifies that only 4 host bits are available. With four bits in the significant octet for the subnet mask, the mask would be 255.255.255.240. 240 yields up the first subnet of 16, with the next subnet of 32, 48, and 64. The first host in subnet 16 is 17. Thus, 192.168.16.17 is the first host. The last host in this subnet is 30, because 192.168.16.31 is the broadcast address for subnet 16.
Note: Do not move on until ALL your students have grasped this.