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
/2211111111111111111111110000000000network bitshost bits

An access list must match the network 172.16.0.0/22. Access lists use a wildcard mask, the inverse of the subnet mask. What is the third octet x of the wildcard mask?

/22
x =
2.Easy
255.255.255.22411111111111111111111111111100000network bitshost bits

A subnet has the mask 255.255.255.224. What is its prefix length p?

255.255.255.224
p =
3.Medium
/?11111111111111111111110000000000network bitshost bits

A department needs 541 host addresses in a single subnet. What is the longest prefix length p (smallest subnet) that is big enough?

541 hosts
p =
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
third octet = 29012806403211618140211networkhost

A host has the address 172.20.29.136/20. What is the third octet x of its network address?

172.20.29.136/20
x =
6.Hard

The network 192.168.225.0/24 is split with VLSM for these LANs: A: 126 hosts, B: 38 hosts, C: 17 hosts, D: 13 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: 126B: 38C: 17D: 13
x =

Answer key

  1. 1. x = 3
  2. 2. p = 27
  3. 3. p = 22
  4. 4. H = 14
  5. 5. x = 16
  6. 6. x = 192

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