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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1.Easy
third octet of /18112816403201608040201oneszeros

Write the subnet mask of a /18 network in dotted-decimal notation. What is the value x of its third octet?

/18
x =
2.Easy
fourth octet of /27112816413201608040201oneszeros

Write the subnet mask of a /27 network in dotted-decimal notation. What is the value x of its fourth octet?

/27
x =
3.Medium
/24 → /2811111111111111111111111111110000network bitshost bits

The network 192.168.108.0/24 is divided into /28 subnets, numbered 1, 2, 3, … from the lowest address (subnet 1 starts at .0). What is the fourth octet x of the broadcast address of subnet 12?

192.168.108.0/24/28subnet 12 (subnet 1 starts at .0)
x =
4.Medium
255.255.254.011111111111111111111111000000000network bitshost bits

A subnet uses the mask 255.255.254.0. How many usable host addresses H does it have?

255.255.254.0
H =
5.Hard
last octet = 157112806403211618140211networkhost

A host has the address 10.20.147.157/27. What is the fourth octet x of its network address?

10.20.147.157/27
x =
6.Hard
third octet 56 … 61012806413211618040201commonvaries

A router has routes to these networks: 10.100.56.0/24, 10.100.57.0/24, 10.100.58.0/24, 10.100.59.0/24, 10.100.60.0/24, 10.100.61.0/24. What is the longest prefix length p of a single summary route that covers all of them?

10.100.56.0/24 … 10.100.61.0/24
p =

Answer key

  1. 1. x = 192
  2. 2. x = 224
  3. 3. x = 191
  4. 4. H = 510
  5. 5. x = 128
  6. 6. p = 21

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