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
/2511111111111111111111111110000000network bitshost bits

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

/25
H =
2.Easy
/2011111111111111111111000000000000network bitshost bits

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

/20
H =
3.Medium
/22 → /2511111111111111111111111110000000network bitshost bits

The network 10.144.132.0/22 is divided into equal subnets with prefix /25. How many subnets N are there?

10.144.132.0/22/25
N =
4.Medium
/16 → /2411111111111111111111111100000000network bitshost bits

The network 172.20.0.0/16 is divided into equal subnets with prefix /24. How many subnets N are there?

172.20.0.0/16/24
N =
5.Hard
third octet = 81012816403211608040211networkhost

A host has the address 172.20.81.23/22. What is the third octet x of its network address?

172.20.81.23/22
x =
6.Hard
third octet 56 … 59012806413211618040201commonvaries

A router has routes to these networks: 10.162.56.0/24, 10.162.57.0/24, 10.162.58.0/24, 10.162.59.0/24. What is the longest prefix length p of a single summary route that covers all of them?

10.162.56.0/24 … 10.162.59.0/24
p =

Answer key

  1. 1. H = 126
  2. 2. H = 4094
  3. 3. N = 8
  4. 4. N = 256
  5. 5. x = 80
  6. 6. p = 22

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