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
/2911111111111111111111111111111000network bitshost bits

How many usable host addresses H are there in an IPv4 subnet with prefix /29?

/29
H =
2.Easy
third octet of /17112806403201608040201oneszeros

Write the subnet mask of a /17 network in dotted-decimal notation. What is the value x of its third octet?

/17
x =
3.Medium
/?11111111111111111111100000000000network bitshost bits

A department needs 1583 host addresses in a single subnet. What is the longest prefix length p (smallest subnet) that is big enough?

1583 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 9 … 16012806403201618040211commonvaries

A router has routes to these networks: 10.15.9.0/24, 10.15.10.0/24, 10.15.11.0/24, 10.15.12.0/24, 10.15.13.0/24, 10.15.14.0/24, 10.15.15.0/24, 10.15.16.0/24. What is the longest prefix length p of a single summary route that covers all of them?

10.15.9.0/24 … 10.15.16.0/24
p =
6.Hard
third octet = 85012816403211608140211networkhost

A host has the address 172.20.85.77/22. What is the third octet x of its network address?

172.20.85.77/22
x =

Answer key

  1. 1. H = 6
  2. 2. x = 128
  3. 3. p = 21
  4. 4. H = 14
  5. 5. p = 19
  6. 6. x = 84

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