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
/1711111111111111111000000000000000network bitshost bits

An access list must match the network 172.16.0.0/17. Access lists use a wildcard mask, the inverse of the subnet mask. What is the third octet x of the wildcard mask?

/17
x =
2.Easy
255.255.192.011111111111111111100000000000000network bitshost bits

A subnet has the mask 255.255.192.0. What is its prefix length p?

255.255.192.0
p =
3.Medium
255.255.255.25211111111111111111111111111111100network bitshost bits

A subnet uses the mask 255.255.255.252. How many usable host addresses H does it have?

255.255.255.252
H =
4.Medium
/24 → /2911111111111111111111111111111000network bitshost bits

The network 192.168.10.0/24 must be divided into at least 20 equal subnets. If you borrow as few bits as possible, how many usable hosts H does each subnet have?

192.168.10.0/2420 subnets
H =
5.Hard
last octet = 219112816403211618041211networkhost

A host has the address 10.20.193.219/25. What is the fourth octet x of its network address?

10.20.193.219/25
x =
6.Hard
third octet = 75012816403201618041211networkhost

A host has the address 172.20.75.91/19. What is the third octet x of its network address?

172.20.75.91/19
x =

Answer key

  1. 1. x = 127
  2. 2. p = 18
  3. 3. H = 2
  4. 4. H = 6
  5. 5. x = 128
  6. 6. x = 64

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