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
255.255.255.12811111111111111111111111110000000network bitshost bits

A subnet has the mask 255.255.255.128. What is its prefix length p?

255.255.255.128
p =
2.Easy
/2411111111111111111111111100000000network bitshost bits

How many usable host addresses H are there in an IPv4 subnet with prefix /24?

/24
H =
3.Medium
/?11111111111111111111110000000000network bitshost bits

A department needs 546 host addresses in a single subnet. What is the longest prefix length p (smallest subnet) that is big enough?

546 hosts
p =
4.Medium
/24 → /2911111111111111111111111111111000network bitshost bits

The network 192.168.138.0/24 is divided into /29 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 5?

192.168.138.0/24/29subnet 5 (subnet 1 starts at .0)
x =
5.Hard
last octet = 28012806403211618140201networkhost

A host has the address 10.20.70.28/25. What is the last number (fourth octet) x of its subnet's broadcast address?

10.20.70.28/25
x =
6.Hard
last octet = 205112816403201618140211networkhost

A host has the address 10.20.79.205/26. What is the last number (fourth octet) x of its subnet's broadcast address?

10.20.79.205/26
x =

Answer key

  1. 1. p = 25
  2. 2. H = 254
  3. 3. p = 22
  4. 4. x = 32
  5. 5. x = 127
  6. 6. x = 255

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