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 /19112816413201608040201oneszeros

Write the subnet mask of a /19 network in dotted-decimal notation. What is the value x of its third octet?

/19
x =
2.Easy
/2111111111111111111111100000000000network bitshost bits

How many usable host addresses H are there in an IPv4 subnet with prefix /21?

/21
H =
3.Medium
/24 → /2511111111111111111111111110000000network bitshost bits

The network 192.168.208.0/24 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?

192.168.208.0/24/25subnet 2 (subnet 1 starts at .0)
x =
4.Medium
/24 → /2711111111111111111111111111100000network bitshost bits

The network 192.168.10.0/24 must be divided into at least 8 equal subnets. If you borrow as few bits as possible, how many usable hosts H does each subnet have?

192.168.10.0/248 subnets
H =
5.Hard
last octet = 215112816403211608141211networkhost

A host has the address 10.20.248.215/29. What is the fourth octet x of the last usable host address in its subnet?

10.20.248.215/29
x =
6.Hard
third octet = 90012816403211618041201networkhost

A host has the address 172.20.90.163/18. What is the third octet x of its subnet's broadcast address?

172.20.90.163/18
x =

Answer key

  1. 1. x = 224
  2. 2. H = 2046
  3. 3. x = 128
  4. 4. H = 30
  5. 5. x = 214
  6. 6. x = 127

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