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
255.255.255.24811111111111111111111111111111000network bitshost bits

A subnet has the mask 255.255.255.248. What is its prefix length p?

255.255.255.248
p =
2.Easy
255.255.192.011111111111111111100000000000000network bitshost bits

A subnet has the mask 255.255.192.0. What is its prefix length p?

255.255.192.0
p =
3.Medium
/?11111111111111111111111100000000network bitshost bits

A department needs 223 host addresses in a single subnet. What is the longest prefix length p (smallest subnet) that is big enough?

223 hosts
p =
4.Medium
/24 → /2711111111111111111111111111100000network bitshost bits

The network 192.168.23.0/24 is divided into /27 subnets, numbered 1, 2, 3, … from the lowest address (subnet 1 starts at .0). What is the fourth octet x of the network address of subnet 6?

192.168.23.0/24/27subnet 6 (subnet 1 starts at .0)
x =
5.Hard
last octet = 81012816403211608040211networkhost

A host has the address 10.20.215.81/25. What is the fourth octet x of the last usable host address in its subnet?

10.20.215.81/25
x =
6.Hard
last octet = 18012806403211608041201networkhost

A host has the address 10.20.154.18/25. What is the last number (fourth octet) x of its subnet's broadcast address?

10.20.154.18/25
x =

Answer key

  1. 1. p = 29
  2. 2. p = 18
  3. 3. p = 24
  4. 4. x = 160
  5. 5. x = 126
  6. 6. x = 127

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