What is DHCP?

The service that automatically gives devices an IP address and other network settings.

In plain English

When a device joins a network it asks for settings. A DHCP server replies with an IP address, the subnet mask, the default gateway and the DNS server to use. The address is usually leased for a set time and renewed. Without DHCP you would have to type these settings into every device by hand.

Example

If a laptop shows an address starting 169.254, it did not get an answer from a DHCP server and gave itself a fallback address.

Easy to confuse with

• DNS: DHCP hands out addresses to devices. DNS turns names into addresses.

Where you will meet it

This idea belongs to the subject area of these practice tests. We do not publish or predict real exam questions.

• Cisco CCST Networking practice tests
• CompTIA Tech+ practice tests
• Cisco CCST IT Support practice tests

Related terms

• DNS: The system that turns names like example.com into the IP addresses computers use.
• Subnet: A smaller network carved out of a larger IP range.
• OSI model: A seven-layer way of describing how data travels across a network.

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