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
/1811111111111111111100000000000000network bitshost bits

An access list must match the network 172.16.0.0/18. Access lists use a wildcard mask, the inverse of the subnet mask. What is the third octet x of the wildcard mask?

/18
x =
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
255.255.248.011111111111111111111100000000000network bitshost bits

A subnet uses the mask 255.255.248.0. How many usable host addresses H does it have?

255.255.248.0
H =
4.Medium
/16 → /1911111111111111111110000000000000network bitshost bits

The network 172.27.0.0/16 is divided into equal subnets with prefix /19. How many subnets N are there?

172.27.0.0/16/19
N =
5.Hard
third octet 203 … 210112816403201618041211commonvaries

A router has routes to these networks: 10.8.203.0/24, 10.8.204.0/24, 10.8.205.0/24, 10.8.206.0/24, 10.8.207.0/24, 10.8.208.0/24, 10.8.209.0/24, 10.8.210.0/24. What is the longest prefix length p of a single summary route that covers all of them?

10.8.203.0/24 … 10.8.210.0/24
p =
6.Hard
third octet = 234112816413201618041201networkhost

A host has the address 172.20.234.26/17. What is the third octet x of its subnet's broadcast address?

172.20.234.26/17
x =

Answer key

  1. 1. x = 63
  2. 2. x = 224
  3. 3. H = 2046
  4. 4. N = 8
  5. 5. p = 19
  6. 6. x = 255

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