IPv4 subnetting worksheet with answers

Free printable IPv4 subnetting worksheet: 6 problems from easy to exam level, with an answer key. Print it or save it as a PDF.

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Name: ____________________   Date: ____________

1.Easy
255.255.252.011111111111111111111110000000000network bitshost bits

A subnet has the mask 255.255.252.0. What is its prefix length p?

255.255.252.0
p =
2.Easy
/2511111111111111111111111110000000network bitshost bits

How many usable host addresses H are there in an IPv4 subnet with prefix /25?

/25
H =
3.Medium
/20 → /2311111111111111111111111000000000network bitshost bits

The network 10.89.16.0/20 is divided into equal subnets with prefix /23. How many subnets N are there?

10.89.16.0/20/23
N =
4.Medium
/24 → /2811111111111111111111111111110000network bitshost bits

The network 192.168.52.0/24 is divided into /28 subnets, numbered 1, 2, 3, … from the lowest address (subnet 1 starts at .0). What is the fourth octet x of the network address of subnet 11?

192.168.52.0/24/28subnet 11 (subnet 1 starts at .0)
x =
5.Hard
third octet 192 … 199112816403201608040201commonvaries

A router has routes to these networks: 10.82.192.0/24, 10.82.193.0/24, 10.82.194.0/24, 10.82.195.0/24, 10.82.196.0/24, 10.82.197.0/24, 10.82.198.0/24, 10.82.199.0/24. What is the longest prefix length p of a single summary route that covers all of them?

10.82.192.0/24 … 10.82.199.0/24
p =
6.Hard
third octet = 25012806403211618040211networkhost

A host has the address 172.20.25.18/20. What is the third octet x of its subnet's broadcast address?

172.20.25.18/20
x =

Answer key

  1. 1. p = 22
  2. 2. H = 126
  3. 3. N = 8
  4. 4. x = 160
  5. 5. p = 21
  6. 6. x = 31

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