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
/2311111111111111111111111000000000network bitshost bits

An access list must match the network 172.16.0.0/23. Access lists use a wildcard mask, the inverse of the subnet mask. What is the third octet x of the wildcard mask?

/23
x =
2.Easy
/2711111111111111111111111111100000network bitshost bits

How many usable host addresses H are there in an IPv4 subnet with prefix /27?

/27
H =
3.Medium
/24 → /2811111111111111111111111111110000network bitshost bits

The network 192.168.211.0/24 is divided into /28 subnets, numbered 1, 2, 3, … from the lowest address (subnet 1 starts at .0). What is the fourth octet x of the network address of subnet 6?

192.168.211.0/24/28subnet 6 (subnet 1 starts at .0)
x =
4.Medium
/?11111111111111111111111111000000network bitshost bits

A department needs 34 host addresses in a single subnet. What is the longest prefix length p (smallest subnet) that is big enough?

34 hosts
p =
5.Hard
third octet = 137112806403201618040211networkhost

A host has the address 172.20.137.45/21. What is the third octet x of its network address?

172.20.137.45/21
x =
6.Hard

The network 192.168.216.0/24 is split with VLSM for these LANs: A: 6 hosts, B: 18 hosts, C: 19 hosts, D: 56 hosts, E: 14 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 E?

A: 6B: 18C: 19D: 56E: 14
x =

Answer key

  1. 1. x = 1
  2. 2. H = 30
  3. 3. x = 80
  4. 4. p = 26
  5. 5. x = 136
  6. 6. x = 128

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