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
/2511111111111111111111111110000000network bitshost bits

How many usable host addresses H are there in an IPv4 subnet with prefix /25?

/25
H =
2.Easy
255.255.248.011111111111111111111100000000000network bitshost bits

A subnet has the mask 255.255.248.0. What is its prefix length p?

255.255.248.0
p =
3.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 =
4.Medium
/24 → /2811111111111111111111111111110000network bitshost bits

The network 192.168.10.0/24 must be divided into at least 12 equal subnets. If you borrow as few bits as possible, how many usable hosts H does each subnet have?

192.168.10.0/2412 subnets
H =
5.Hard

The network 192.168.137.0/24 is split with VLSM for these LANs: A: 21 hosts, B: 76 hosts, C: 27 hosts, D: 3 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 D?

A: 21B: 76C: 27D: 3
x =
6.Hard
last octet = 50012806413211608041201networkhost

A host has the address 10.20.206.50/25. What is the last number (fourth octet) x of its subnet's broadcast address?

10.20.206.50/25
x =

Answer key

  1. 1. H = 126
  2. 2. p = 21
  3. 3. H = 510
  4. 4. H = 14
  5. 5. x = 192
  6. 6. x = 127

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