Subnetting question(s)

linuxlover

Hi, I went over a Subnetting section by Chris Bryant (CCNA@Udemy) and actually now that I understand it, I feel like this is pretty simple stuff. I have started practising @ subnettingquestions.com and I already have a problem.

Question: What is the first valid host on the subnetwork that the node 172.23.80.9/21 belongs to?
Answer: 172.23.80.1


I don't understand why the answer is 172.23.80.1 and not 172.23.80.10?

networker050184

You need to figure out what network that address belongs to, not just start the network there.

Jon_Cisco

The address provided is within a range. You need to translate the /21 to understand the range.

172.23.80.0 is the network
172.23.80.1 is the first host
172.23.87.255 is the broadcast
172.23.88.0 is the next network

linuxlover

You're right, I was asking myself the wrong question. I was calculating the IP range (as if the address was a subnet) when I should've calculated which subnet is the address on. Thanks for the hint.

jayskata

try Subnetting Practice Questions!