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
255.255.255.24811111111111111111111111111111000network bitshost bits

A subnet has the mask 255.255.255.248. What is its prefix length p?

255.255.255.248
p =
2.Easy
/2811111111111111111111111111110000network bitshost bits

How many usable host addresses H are there in an IPv4 subnet with prefix /28?

/28
H =
3.Medium
/?11111111111111111111100000000000network bitshost bits

A department needs 1236 host addresses in a single subnet. What is the longest prefix length p (smallest subnet) that is big enough?

1236 hosts
p =
4.Medium
/24 → /2811111111111111111111111111110000network bitshost bits

The network 192.168.10.0/24 must be divided into at least 10 equal subnets. If you borrow as few bits as possible, how many usable hosts H does each subnet have?

192.168.10.0/2410 subnets
H =
5.Hard
third octet = 186112806413211618041201networkhost

A host has the address 172.20.186.196/23. What is the third octet x of its subnet's broadcast address?

172.20.186.196/23
x =
6.Hard
third octet 5 … 7012806403201608140211commonvaries

A router has routes to these networks: 10.209.5.0/24, 10.209.6.0/24, 10.209.7.0/24. What is the longest prefix length p of a single summary route that covers all of them?

10.209.5.0/24 … 10.209.7.0/24
p =

Answer key

  1. 1. p = 29
  2. 2. H = 14
  3. 3. p = 21
  4. 4. H = 14
  5. 5. x = 187
  6. 6. p = 22

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