General

Question 1

You have a corporate network of size 10.0.0.0/8 and a satellite office of size 192.168.0.0/16. Which CIDR is acceptable for your AWS VPC if you plan on connecting your networks later on?

• 172.16.0.0/12
• 172.16.0.0/16
• 10.0.16.0/16
• 192.168.4.0/18

Answer 1

172.16.0.0/16 because CIDRs cannot overlap and the max CIDR size in AWS is 16

Question 2

What does a subnet mask in a cidr range do?

Answer 2

It determines how many bits can change in the IP (XX.XX.XX.XX)

Question 3

In a /32 CIDR, what IP number can change?

Answer 3

None, 32 represents 1 IP

Question 4

In a /24 CIDR, what IP number can change?

Answer 4

The last number can change : XX.XX.XX.11

Question 5

In a /16 CIDR, what IP number can change?

Answer 5

The last 2 numbers can change XX.XX.11.22

Question 6

In a /8 CIDR, what IP number can change?

Answer 6

The last 3 numbers can change XX.11.22.33

Question 7

In a /0 CIDR, what IP number can change?

Answer 7

All IP numbers can change 11.22.33.44

Question 8

If you have CIDR 192.168.0.0/24, how many IPs does it represent and what is the first and last IP?

Answer 8

• It represents 256 IPs (2^8)
• The first IP is 192.168.0.0
• The last IP is 192.168.0.255