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
third octet of /18112816403201608040201oneszeros

Write the subnet mask of a /18 network in dotted-decimal notation. What is the value x of its third octet?

/18
x =
2.Easy
/2511111111111111111111111110000000network bitshost bits

How many usable host addresses H are there in an IPv4 subnet with prefix /25?

/25
H =
3.Medium
/24 → /2611111111111111111111111111000000network bitshost bits

The network 192.168.10.0/24 must be divided into at least 3 equal subnets. If you borrow as few bits as possible, how many usable hosts H does each subnet have?

192.168.10.0/243 subnets
H =
4.Medium
/24 → /3011111111111111111111111111111100network bitshost bits

The network 10.131.21.0/24 is divided into equal subnets with prefix /30. How many subnets N are there?

10.131.21.0/24/30
N =
5.Hard
third octet = 85012816403211608140211networkhost

A host has the address 172.20.85.185/20. What is the third octet x of its network address?

172.20.85.185/20
x =
6.Hard
last octet = 245112816413211608140211networkhost

A host has the address 10.20.46.245/30. What is the last number (fourth octet) x of its subnet's broadcast address?

10.20.46.245/30
x =

Answer key

  1. 1. x = 192
  2. 2. H = 126
  3. 3. H = 62
  4. 4. N = 64
  5. 5. x = 80
  6. 6. x = 247

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