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
/2911111111111111111111111111111000network bitshost bits

An access list must match the network 192.168.1.0/29. Access lists use a wildcard mask, the inverse of the subnet mask. What is the fourth octet x of the wildcard mask?

/29
x =
2.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 =
3.Medium
/24 → /2711111111111111111111111111100000network bitshost bits

The network 192.168.45.0/24 is divided into /27 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?

192.168.45.0/24/27subnet 2 (subnet 1 starts at .0)
x =
4.Medium
/24 → /2611111111111111111111111111000000network bitshost bits

The network 192.168.10.0/24 must be divided into at least 4 equal subnets. If you borrow as few bits as possible, how many usable hosts H does each subnet have?

192.168.10.0/244 subnets
H =
5.Hard
third octet 42 … 43012806413201618041201commonvaries

A router has routes to these networks: 10.81.42.0/24, 10.81.43.0/24. What is the longest prefix length p of a single summary route that covers all of them?

10.81.42.0/24 … 10.81.43.0/24
p =
6.Hard
last octet = 139112806403201618041211networkhost

A host has the address 10.20.11.139/25. What is the fourth octet x of the last usable host address in its subnet?

10.20.11.139/25
x =

Answer key

  1. 1. x = 7
  2. 2. p = 19
  3. 3. x = 32
  4. 4. H = 62
  5. 5. p = 23
  6. 6. x = 254

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