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
third octet of /21112816413211618040201oneszeros

Write the subnet mask of a /21 network in dotted-decimal notation. What is the value x of its third octet?

/21
x =
3.Medium
/?11111111111111111111100000000000network bitshost bits

A department needs 1551 host addresses in a single subnet. What is the longest prefix length p (smallest subnet) that is big enough?

1551 hosts
p =
4.Medium
/?11111111111111111111100000000000network bitshost bits

A department needs 1275 host addresses in a single subnet. What is the longest prefix length p (smallest subnet) that is big enough?

1275 hosts
p =
5.Hard
last octet = 19012806403211608041211networkhost

A host has the address 10.20.110.19/28. What is the fourth octet x of the last usable host address in its subnet?

10.20.110.19/28
x =
6.Hard
last octet = 225112816413201608040211networkhost

A host has the address 10.20.246.225/26. What is the last number (fourth octet) x of its subnet's broadcast address?

10.20.246.225/26
x =

Answer key

  1. 1. p = 29
  2. 2. x = 248
  3. 3. p = 21
  4. 4. p = 21
  5. 5. x = 30
  6. 6. x = 255

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