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 /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
/2011111111111111111111000000000000network bitshost bits

How many usable host addresses H are there in an IPv4 subnet with prefix /20?

/20
H =
3.Medium
255.255.255.12811111111111111111111111110000000network bitshost bits

A subnet uses the mask 255.255.255.128. How many usable host addresses H does it have?

255.255.255.128
H =
4.Medium
255.255.255.22411111111111111111111111111100000network bitshost bits

A subnet uses the mask 255.255.255.224. How many usable host addresses H does it have?

255.255.255.224
H =
5.Hard
third octet 217 … 220112816403211618040211commonvaries

A router has routes to these networks: 10.212.217.0/24, 10.212.218.0/24, 10.212.219.0/24, 10.212.220.0/24. What is the longest prefix length p of a single summary route that covers all of them?

10.212.217.0/24 … 10.212.220.0/24
p =
6.Hard

The network 192.168.116.0/24 is split with VLSM for these LANs: A: 13 hosts, B: 4 hosts, C: 21 hosts, D: 45 hosts, E: 19 hosts. Subnets are allocated from .0 upwards, the LAN with the most hosts first, each with the smallest subnet that fits. What is the fourth octet x of the network address of LAN A?

A: 13B: 4C: 21D: 45E: 19
x =

Answer key

  1. 1. x = 192
  2. 2. H = 4094
  3. 3. H = 126
  4. 4. H = 30
  5. 5. p = 21
  6. 6. x = 128

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