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
fourth octet of /25112806403201608040201oneszeros

Write the subnet mask of a /25 network in dotted-decimal notation. What is the value x of its fourth octet?

/25
x =
3.Medium
/24 → /2911111111111111111111111111111000network bitshost bits

The network 192.168.10.0/24 must be divided into at least 20 equal subnets. If you borrow as few bits as possible, how many usable hosts H does each subnet have?

192.168.10.0/2420 subnets
H =
4.Medium
/?11111111111111111111100000000000network bitshost bits

A department needs 1292 host addresses in a single subnet. What is the longest prefix length p (smallest subnet) that is big enough?

1292 hosts
p =
5.Hard
last octet = 201112816403201618040211networkhost

A host has the address 10.20.115.201/30. What is the last number (fourth octet) x of its subnet's broadcast address?

10.20.115.201/30
x =
6.Hard
third octet 142 … 148112806403201618141201commonvaries

A router has routes to these networks: 10.38.142.0/24, 10.38.143.0/24, 10.38.144.0/24, 10.38.145.0/24, 10.38.146.0/24, 10.38.147.0/24, 10.38.148.0/24. What is the longest prefix length p of a single summary route that covers all of them?

10.38.142.0/24 … 10.38.148.0/24
p =

Answer key

  1. 1. p = 19
  2. 2. x = 128
  3. 3. H = 6
  4. 4. p = 21
  5. 5. x = 203
  6. 6. p = 19

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