Computer Networking · Beginner level

Beginner level · Module 1: IP Addresses, Routers and Switches · Lesson 2 of 3

IP Addresses and DHCP

Read and understand the addresses that identify devices.

In this lesson you will

  • Read IPv4 settings
  • Explain private addresses and DHCP

Key concepts

IPv4 addresssubnet maskdefault gatewayDHCP

The lesson

An IPv4 address such as 192.168.1.25 identifies a device on a network. The subnet mask (often 255.255.255.0) shows which part is the network and which is the device.

Private ranges — 10.0.0.0/8, 172.16.0.0/12 and 192.168.0.0/16 (defined in RFC 1918) — are used inside organisations; the router translates them to a public address for the internet.

DHCP automatically gives each device an address, mask, default gateway (the router) and DNS servers, so users do not configure them by hand.

Step by step

  1. Run ipconfig (Windows) or check Wi-Fi details on a phone.
  2. Record address, mask, gateway and DNS.
  3. Identify whether the address is private.
  4. Explain where the settings came from.

Practice activity

Complete the IP settings worksheet for two devices.

Expected result: Correct settings recorded and explained.

Check your understanding

  1. Is 192.168.1.25 a private or public address?

    Show answer

    Private.

  2. What does DHCP provide?

    Show answer

    An IP address, subnet mask, default gateway and DNS servers.

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