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.

New worksheetPractise online with hints

For teachers: free to print, copy and use in class. Every new worksheet has new values and its own answer key. A link to ExamProblems on your course page is appreciated.

Name: ____________________   Date: ____________

1.Easy
/2511111111111111111111111110000000network bitshost bits

How many usable host addresses H are there in an IPv4 subnet with prefix /25?

/25
H =
2.Easy
third octet of /20112816413211608040201oneszeros

Write the subnet mask of a /20 network in dotted-decimal notation. What is the value x of its third octet?

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

The network 192.168.10.0/24 must be divided into at least 5 equal subnets. If you borrow as few bits as possible, how many usable hosts H does each subnet have?

192.168.10.0/245 subnets
H =
4.Medium
/24 → /2511111111111111111111111110000000network bitshost bits

The network 192.168.91.0/24 is divided into /25 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 2?

192.168.91.0/24/25subnet 2 (subnet 1 starts at .0)
x =
5.Hard
third octet 128 … 129112806403201608040201commonvaries

A router has routes to these networks: 10.131.128.0/24, 10.131.129.0/24. What is the longest prefix length p of a single summary route that covers all of them?

10.131.128.0/24 … 10.131.129.0/24
p =
6.Hard
last octet = 95012816403211618141211networkhost

A host has the address 10.20.227.95/27. What is the fourth octet x of the last usable host address in its subnet?

10.20.227.95/27
x =

Answer key

  1. 1. H = 126
  2. 2. x = 240
  3. 3. H = 30
  4. 4. x = 128
  5. 5. p = 23
  6. 6. x = 94

Full step-by-step solutions: practise this topic on examproblems.com.