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
/2611111111111111111111111111000000network bitshost bits

How many usable host addresses H are there in an IPv4 subnet with prefix /26?

/26
H =
3.Medium
/?11111111111111111111111100000000network bitshost bits

A department needs 236 host addresses in a single subnet. What is the longest prefix length p (smallest subnet) that is big enough?

236 hosts
p =
4.Medium
/24 → /2711111111111111111111111111100000network bitshost bits

The network 10.89.138.0/24 is divided into equal subnets with prefix /27. How many subnets N are there?

10.89.138.0/24/27
N =
5.Hard
third octet = 245112816413211608140211networkhost

A host has the address 172.20.245.224/20. What is the third octet x of its subnet's broadcast address?

172.20.245.224/20
x =
6.Hard

The network 192.168.48.0/24 is split with VLSM for these LANs: A: 41 hosts, B: 13 hosts, C: 25 hosts, D: 81 hosts. Subnets are allocated from .0 upwards, the LAN with the most hosts first, each with the smallest subnet that fits. What is the fourth octet x of the network address of LAN B?

A: 41B: 13C: 25D: 81
x =

Answer key

  1. 1. x = 128
  2. 2. H = 62
  3. 3. p = 24
  4. 4. N = 8
  5. 5. x = 255
  6. 6. x = 224

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