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
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
/24 → /2811111111111111111111111111110000network bitshost bits

The network 192.168.10.0/24 must be divided into at least 10 equal subnets. If you borrow as few bits as possible, how many usable hosts H does each subnet have?

192.168.10.0/2410 subnets
H =
4.Medium
/16 → /2111111111111111111111100000000000network bitshost bits

The network 172.17.0.0/16 is divided into equal subnets with prefix /21. How many subnets N are there?

172.17.0.0/16/21
N =
5.Hard
last octet = 113012816413211608040211networkhost

A host has the address 10.20.98.113/29. What is the last number (fourth octet) x of its subnet's broadcast address?

10.20.98.113/29
x =
6.Hard
third octet 136 … 143112806403201618040201commonvaries

A router has routes to these networks: 10.22.136.0/24, 10.22.137.0/24, 10.22.138.0/24, 10.22.139.0/24, 10.22.140.0/24, 10.22.141.0/24, 10.22.142.0/24, 10.22.143.0/24. What is the longest prefix length p of a single summary route that covers all of them?

10.22.136.0/24 … 10.22.143.0/24
p =

Answer key

  1. 1. H = 126
  2. 2. p = 22
  3. 3. H = 14
  4. 4. N = 32
  5. 5. x = 119
  6. 6. p = 21

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