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

Write the subnet mask of a /19 network in dotted-decimal notation. What is the value x of its third octet?

/19

x =

2.Easy

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

/21

H =

3.Medium

The network 192.168.87.0/24 is divided into /25 subnets, numbered 1, 2, 3, … from the lowest address (subnet 1 starts at .0). What is the fourth octet x of the network address of subnet 2?

192.168.87.0/24/25subnet 2 (subnet 1 starts at .0)

x =

4.Medium

The network 192.168.69.0/24 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 network address of subnet 5?

192.168.69.0/24/27subnet 5 (subnet 1 starts at .0)

x =

5.Hard

A host has the address 10.20.151.127/27. What is the fourth octet x of the last usable host address in its subnet?

10.20.151.127/27

x =

6.Hard

A router has routes to these networks: 10.173.70.0/24, 10.173.71.0/24, 10.173.72.0/24, 10.173.73.0/24, 10.173.74.0/24, 10.173.75.0/24, 10.173.76.0/24, 10.173.77.0/24. What is the longest prefix length p of a single summary route that covers all of them?

10.173.70.0/24 … 10.173.77.0/24

p =

Answer key

1. x = 224
2. H = 2046
3. x = 128
4. x = 128
5. x = 126
6. p = 20

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