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
fourth octet of /25112806403201608040201oneszeros

Write the subnet mask of a /25 network in dotted-decimal notation. What is the value x of its fourth octet?

/25
x =
2.Easy
/2211111111111111111111110000000000network bitshost bits

An access list must match the network 172.16.0.0/22. Access lists use a wildcard mask, the inverse of the subnet mask. What is the third octet x of the wildcard mask?

/22
x =
3.Medium
/20 → /2711111111111111111111111111100000network bitshost bits

The network 10.139.48.0/20 is divided into equal subnets with prefix /27. How many subnets N are there?

10.139.48.0/20/27
N =
4.Medium
/?11111111111111111111100000000000network bitshost bits

A department needs 1930 host addresses in a single subnet. What is the longest prefix length p (smallest subnet) that is big enough?

1930 hosts
p =
5.Hard
last octet = 188112806413211618140201networkhost

A host has the address 10.20.74.188/30. What is the fourth octet x of its network address?

10.20.74.188/30
x =
6.Hard
last octet = 143112806403201618141211networkhost

A host has the address 10.20.146.143/25. What is the fourth octet x of its network address?

10.20.146.143/25
x =

Answer key

  1. 1. x = 128
  2. 2. x = 3
  3. 3. N = 128
  4. 4. p = 21
  5. 5. x = 188
  6. 6. x = 128

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