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
/2111111111111111111111100000000000network bitshost bits

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

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

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

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

The network 192.168.10.0/24 must be divided into at least 5 equal subnets. If you borrow as few bits as possible, how many usable hosts H does each subnet have?

192.168.10.0/245 subnets
H =
5.Hard
last octet = 74012816403201618041201networkhost

A host has the address 10.20.9.74/25. What is the fourth octet x of the last usable host address in its subnet?

10.20.9.74/25
x =
6.Hard

The network 192.168.225.0/24 is split with VLSM for these LANs: A: 14 hosts, B: 54 hosts, C: 24 hosts, D: 4 hosts, E: 7 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 C?

A: 14B: 54C: 24D: 4E: 7
x =

Answer key

  1. 1. H = 2046
  2. 2. H = 126
  3. 3. H = 30
  4. 4. H = 30
  5. 5. x = 126
  6. 6. x = 64

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