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
/2011111111111111111111000000000000network bitshost bits

How many usable host addresses H are there in an IPv4 subnet with prefix /20?

/20
H =
2.Easy
/2511111111111111111111111110000000network bitshost bits

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

/25
H =
3.Medium
/16 → /2011111111111111111111000000000000network bitshost bits

The network 172.19.0.0/16 is divided into equal subnets with prefix /20. How many subnets N are there?

172.19.0.0/16/20
N =
4.Medium
/?11111111111111111111110000000000network bitshost bits

A department needs 964 host addresses in a single subnet. What is the longest prefix length p (smallest subnet) that is big enough?

964 hosts
p =
5.Hard
third octet = 112012816413211608040201networkhost

A host has the address 172.20.112.94/23. What is the third octet x of its subnet's broadcast address?

172.20.112.94/23
x =
6.Hard
third octet 20 … 23012806403211608140201commonvaries

A router has routes to these networks: 10.187.20.0/24, 10.187.21.0/24, 10.187.22.0/24, 10.187.23.0/24. What is the longest prefix length p of a single summary route that covers all of them?

10.187.20.0/24 … 10.187.23.0/24
p =

Answer key

  1. 1. H = 4094
  2. 2. H = 126
  3. 3. N = 16
  4. 4. p = 22
  5. 5. x = 113
  6. 6. p = 22

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