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
255.255.248.011111111111111111111100000000000network bitshost bits

A subnet has the mask 255.255.248.0. What is its prefix length p?

255.255.248.0
p =
2.Easy
/2011111111111111111111000000000000network bitshost bits

How many usable host addresses H are there in an IPv4 subnet with prefix /20?

/20
H =
3.Medium
/24 → /2711111111111111111111111111100000network bitshost bits

The network 192.168.10.0/24 must be divided into at least 8 equal subnets. If you borrow as few bits as possible, how many usable hosts H does each subnet have?

192.168.10.0/248 subnets
H =
4.Medium
255.255.255.25211111111111111111111111111111100network bitshost bits

A subnet uses the mask 255.255.255.252. How many usable host addresses H does it have?

255.255.255.252
H =
5.Hard
last octet = 105012816413201618040211networkhost

A host has the address 10.20.75.105/28. What is the last number (fourth octet) x of its subnet's broadcast address?

10.20.75.105/28
x =
6.Hard
third octet = 156112806403211618140201networkhost

A host has the address 172.20.156.117/21. What is the third octet x of its network address?

172.20.156.117/21
x =

Answer key

  1. 1. p = 21
  2. 2. H = 4094
  3. 3. H = 30
  4. 4. H = 2
  5. 5. x = 111
  6. 6. x = 152

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