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
/2711111111111111111111111111100000network bitshost bits

How many usable host addresses H are there in an IPv4 subnet with prefix /27?

/27
H =
2.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 =
3.Medium
/22 → /3011111111111111111111111111111100network bitshost bits

The network 10.170.124.0/22 is divided into equal subnets with prefix /30. How many subnets N are there?

10.170.124.0/22/30
N =
4.Medium
255.255.248.011111111111111111111100000000000network bitshost bits

A subnet uses the mask 255.255.248.0. How many usable host addresses H does it have?

255.255.248.0
H =
5.Hard
third octet 102 … 108012816413201608141201commonvaries

A router has routes to these networks: 10.132.102.0/24, 10.132.103.0/24, 10.132.104.0/24, 10.132.105.0/24, 10.132.106.0/24, 10.132.107.0/24, 10.132.108.0/24. What is the longest prefix length p of a single summary route that covers all of them?

10.132.102.0/24 … 10.132.108.0/24
p =
6.Hard
last octet = 123012816413211618041211networkhost

A host has the address 10.20.31.123/25. What is the last number (fourth octet) x of its subnet's broadcast address?

10.20.31.123/25
x =

Answer key

  1. 1. H = 30
  2. 2. p = 22
  3. 3. N = 256
  4. 4. H = 2046
  5. 5. p = 20
  6. 6. x = 127

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