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
255.255.255.12811111111111111111111111110000000network bitshost bits

A subnet has the mask 255.255.255.128. What is its prefix length p?

255.255.255.128
p =
2.Easy
fourth octet of /30112816413211618140201oneszeros

Write the subnet mask of a /30 network in dotted-decimal notation. What is the value x of its fourth octet?

/30
x =
3.Medium
/16 → /2411111111111111111111111100000000network bitshost bits

The network 172.17.0.0/16 is divided into equal subnets with prefix /24. How many subnets N are there?

172.17.0.0/16/24
N =
4.Medium
/?11111111111111111111100000000000network bitshost bits

A department needs 1561 host addresses in a single subnet. What is the longest prefix length p (smallest subnet) that is big enough?

1561 hosts
p =
5.Hard
third octet = 166112806413201608141201networkhost

A host has the address 172.20.166.135/21. What is the third octet x of its subnet's broadcast address?

172.20.166.135/21
x =
6.Hard
last octet = 190112806413211618141201networkhost

A host has the address 10.20.62.190/28. What is the last number (fourth octet) x of its subnet's broadcast address?

10.20.62.190/28
x =

Answer key

  1. 1. p = 25
  2. 2. x = 252
  3. 3. N = 256
  4. 4. p = 21
  5. 5. x = 167
  6. 6. x = 191

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