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
third octet of /21112816413211618040201oneszeros

Write the subnet mask of a /21 network in dotted-decimal notation. What is the value x of its third octet?

/21
x =
2.Easy
/2511111111111111111111111110000000network bitshost bits

An access list must match the network 192.168.1.0/25. Access lists use a wildcard mask, the inverse of the subnet mask. What is the fourth octet x of the wildcard mask?

/25
x =
3.Medium
/24 → /2711111111111111111111111111100000network bitshost bits

The network 192.168.10.0/24 must be divided into at least 6 equal subnets. If you borrow as few bits as possible, how many usable hosts H does each subnet have?

192.168.10.0/246 subnets
H =
4.Medium
/20 → /2711111111111111111111111111100000network bitshost bits

The network 10.122.80.0/20 is divided into equal subnets with prefix /27. How many subnets N are there?

10.122.80.0/20/27
N =
5.Hard
last octet = 212112816403211608140201networkhost

A host has the address 10.20.4.212/25. What is the last number (fourth octet) x of its subnet's broadcast address?

10.20.4.212/25
x =
6.Hard
last octet = 189112806413211618140211networkhost

A host has the address 10.20.95.189/25. What is the fourth octet x of its network address?

10.20.95.189/25
x =

Answer key

  1. 1. x = 248
  2. 2. x = 127
  3. 3. H = 30
  4. 4. N = 128
  5. 5. x = 255
  6. 6. x = 128

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