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

How many usable host addresses H are there in an IPv4 subnet with prefix /28?

/28

H =

2.Easy

An access list must match the network 172.16.0.0/20. Access lists use a wildcard mask, the inverse of the subnet mask. What is the third octet x of the wildcard mask?

/20

x =

3.Medium

A department needs 1784 host addresses in a single subnet. What is the longest prefix length p (smallest subnet) that is big enough?

1784 hosts

p =

4.Medium

A department needs 829 host addresses in a single subnet. What is the longest prefix length p (smallest subnet) that is big enough?

829 hosts

p =

5.Hard

A router has routes to these networks: 10.96.126.0/24, 10.96.127.0/24, 10.96.128.0/24, 10.96.129.0/24, 10.96.130.0/24, 10.96.131.0/24, 10.96.132.0/24. What is the longest prefix length p of a single summary route that covers all of them?

10.96.126.0/24 … 10.96.132.0/24

p =

6.Hard

The network 192.168.254.0/24 is split with VLSM for these LANs: A: 14 hosts, B: 29 hosts, C: 5 hosts, D: 47 hosts, E: 28 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 B?

A: 14B: 29C: 5D: 47E: 28

x =

Answer key

1. H = 14
2. x = 15
3. p = 21
4. p = 22
5. p = 16
6. x = 64

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