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
255.255.224.011111111111111111110000000000000network bitshost bits

A subnet has the mask 255.255.224.0. What is its prefix length p?

255.255.224.0
p =
2.Easy
/2111111111111111111111100000000000network bitshost bits

How many usable host addresses H are there in an IPv4 subnet with prefix /21?

/21
H =
3.Medium
/24 → /2811111111111111111111111111110000network bitshost bits

The network 192.168.10.0/24 must be divided into at least 16 equal subnets. If you borrow as few bits as possible, how many usable hosts H does each subnet have?

192.168.10.0/2416 subnets
H =
4.Medium
/24 → /2711111111111111111111111111100000network bitshost bits

The network 192.168.89.0/24 is divided into /27 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 8?

192.168.89.0/24/27subnet 8 (subnet 1 starts at .0)
x =
5.Hard
last octet = 73012816403201618040211networkhost

A host has the address 10.20.41.73/29. What is the last number (fourth octet) x of its subnet's broadcast address?

10.20.41.73/29
x =
6.Hard
third octet 176 … 178112806413211608040201commonvaries

A router has routes to these networks: 10.73.176.0/24, 10.73.177.0/24, 10.73.178.0/24. What is the longest prefix length p of a single summary route that covers all of them?

10.73.176.0/24 … 10.73.178.0/24
p =

Answer key

  1. 1. p = 19
  2. 2. H = 2046
  3. 3. H = 14
  4. 4. x = 224
  5. 5. x = 79
  6. 6. p = 22

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