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
255.255.254.011111111111111111111111000000000network bitshost bits

A subnet has the mask 255.255.254.0. What is its prefix length p?

255.255.254.0
p =
2.Easy
third octet of /19112816413201608040201oneszeros

Write the subnet mask of a /19 network in dotted-decimal notation. What is the value x of its third octet?

/19
x =
3.Medium
/20 → /2711111111111111111111111111100000network bitshost bits

The network 10.196.240.0/20 is divided into equal subnets with prefix /27. How many subnets N are there?

10.196.240.0/20/27
N =
4.Medium
/?11111111111111111111110000000000network bitshost bits

A department needs 995 host addresses in a single subnet. What is the longest prefix length p (smallest subnet) that is big enough?

995 hosts
p =
5.Hard
third octet 182 … 187112806413211608141201commonvaries

A router has routes to these networks: 10.81.182.0/24, 10.81.183.0/24, 10.81.184.0/24, 10.81.185.0/24, 10.81.186.0/24, 10.81.187.0/24. What is the longest prefix length p of a single summary route that covers all of them?

10.81.182.0/24 … 10.81.187.0/24
p =
6.Hard
last octet = 249112816413211618040211networkhost

A host has the address 10.20.85.249/30. What is the fourth octet x of the last usable host address in its subnet?

10.20.85.249/30
x =

Answer key

  1. 1. p = 23
  2. 2. x = 224
  3. 3. N = 128
  4. 4. p = 22
  5. 5. p = 20
  6. 6. x = 250

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