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
/2911111111111111111111111111111000network bitshost bits

How many usable host addresses H are there in an IPv4 subnet with prefix /29?

/29
H =
3.Medium
255.255.255.12811111111111111111111111110000000network bitshost bits

A subnet uses the mask 255.255.255.128. How many usable host addresses H does it have?

255.255.255.128
H =
4.Medium
/?11111111111111111111100000000000network bitshost bits

A department needs 1739 host addresses in a single subnet. What is the longest prefix length p (smallest subnet) that is big enough?

1739 hosts
p =
5.Hard
third octet = 185112806413211618040211networkhost

A host has the address 172.20.185.40/17. What is the third octet x of its network address?

172.20.185.40/17
x =
6.Hard
third octet 63 … 70012806413211618141211commonvaries

A router has routes to these networks: 10.141.63.0/24, 10.141.64.0/24, 10.141.65.0/24, 10.141.66.0/24, 10.141.67.0/24, 10.141.68.0/24, 10.141.69.0/24, 10.141.70.0/24. What is the longest prefix length p of a single summary route that covers all of them?

10.141.63.0/24 … 10.141.70.0/24
p =

Answer key

  1. 1. H = 4094
  2. 2. H = 6
  3. 3. H = 126
  4. 4. p = 21
  5. 5. x = 128
  6. 6. p = 17

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