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
/2011111111111111111111000000000000network bitshost bits

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

/20
H =
3.Medium
255.255.255.24011111111111111111111111111110000network bitshost bits

A subnet uses the mask 255.255.255.240. How many usable host addresses H does it have?

255.255.255.240
H =
4.Medium
/?11111111111111111111100000000000network bitshost bits

A department needs 1380 host addresses in a single subnet. What is the longest prefix length p (smallest subnet) that is big enough?

1380 hosts
p =
5.Hard
third octet 9 … 14012806403201618040211commonvaries

A router has routes to these networks: 10.181.9.0/24, 10.181.10.0/24, 10.181.11.0/24, 10.181.12.0/24, 10.181.13.0/24, 10.181.14.0/24. What is the longest prefix length p of a single summary route that covers all of them?

10.181.9.0/24 … 10.181.14.0/24
p =
6.Hard
last octet = 112012816413211608040201networkhost

A host has the address 10.20.32.112/27. What is the last number (fourth octet) x of its subnet's broadcast address?

10.20.32.112/27
x =

Answer key

  1. 1. H = 30
  2. 2. H = 4094
  3. 3. H = 14
  4. 4. p = 21
  5. 5. p = 21
  6. 6. x = 127

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