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
/2111111111111111111111100000000000network bitshost bits

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

/21
H =
2.Easy
third octet of /23112816413211618141201oneszeros

Write the subnet mask of a /23 network in dotted-decimal notation. What is the value x of its third octet?

/23
x =
3.Medium
/24 → /2611111111111111111111111111000000network bitshost bits

The network 192.168.10.0/24 must be divided into at least 3 equal subnets. If you borrow as few bits as possible, how many usable hosts H does each subnet have?

192.168.10.0/243 subnets
H =
4.Medium
255.255.255.24011111111111111111111111111110000network bitshost bits

A subnet uses the mask 255.255.255.240. How many usable host addresses H does it have?

255.255.255.240
H =
5.Hard
last octet = 69012816403201608140211networkhost

A host has the address 10.20.67.69/29. What is the fourth octet x of the last usable host address in its subnet?

10.20.67.69/29
x =
6.Hard
third octet 76 … 81012816403201618140201commonvaries

A router has routes to these networks: 10.151.76.0/24, 10.151.77.0/24, 10.151.78.0/24, 10.151.79.0/24, 10.151.80.0/24, 10.151.81.0/24. What is the longest prefix length p of a single summary route that covers all of them?

10.151.76.0/24 … 10.151.81.0/24
p =

Answer key

  1. 1. H = 2046
  2. 2. x = 254
  3. 3. H = 62
  4. 4. H = 14
  5. 5. x = 70
  6. 6. p = 19

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