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
/2611111111111111111111111111000000network bitshost bits

How many usable host addresses H are there in an IPv4 subnet with prefix /26?

/26
H =
2.Easy
/2111111111111111111111100000000000network bitshost bits

An access list must match the network 172.16.0.0/21. Access lists use a wildcard mask, the inverse of the subnet mask. What is the third octet x of the wildcard mask?

/21
x =
3.Medium
/24 → /2711111111111111111111111111100000network bitshost bits

The network 192.168.10.0/24 must be divided into at least 6 equal subnets. If you borrow as few bits as possible, how many usable hosts H does each subnet have?

192.168.10.0/246 subnets
H =
4.Medium
/24 → /2711111111111111111111111111100000network bitshost bits

The network 192.168.56.0/24 is divided into /27 subnets, numbered 1, 2, 3, … from the lowest address (subnet 1 starts at .0). What is the fourth octet x of the broadcast address of subnet 3?

192.168.56.0/24/27subnet 3 (subnet 1 starts at .0)
x =
5.Hard
third octet 232 … 235112816413201618040201commonvaries

A router has routes to these networks: 10.106.232.0/24, 10.106.233.0/24, 10.106.234.0/24, 10.106.235.0/24. What is the longest prefix length p of a single summary route that covers all of them?

10.106.232.0/24 … 10.106.235.0/24
p =
6.Hard
third octet 188 … 191112806413211618140201commonvaries

A router has routes to these networks: 10.166.188.0/24, 10.166.189.0/24, 10.166.190.0/24, 10.166.191.0/24. What is the longest prefix length p of a single summary route that covers all of them?

10.166.188.0/24 … 10.166.191.0/24
p =

Answer key

  1. 1. H = 62
  2. 2. x = 7
  3. 3. H = 30
  4. 4. x = 95
  5. 5. p = 22
  6. 6. p = 22

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