What is DNS?
The system that turns names like example.com into the IP addresses computers use.
In plain English
People remember names and computers route by numbers. When you type a web address, your device asks a DNS server for the matching IP address, and often remembers the answer for a while (caching). Different record types hold different answers, such as A for an IPv4 address, AAAA for IPv6, CNAME for an alias and MX for mail servers.
Example
If a website loads by its IP address but not by its name, DNS is the first thing to check.
Easy to confuse with
- DHCP: DNS answers “what address does this name have?” DHCP answers “what address should this device use?”
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 We do not publish or predict real exam questions.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
- DHCP: The service that automatically gives devices an IP address and other network settings.
- OSI model: A seven-layer way of describing how data travels across a network.
- Subnet: A smaller network carved out of a larger IP range.
Test yourself
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Browse practice testsAll glossary termsWritten and checked by the Be Ready Education team, last reviewed 2 November 2026. General study information, not professional advice. Providers change names and rules, so confirm details on the official documentation. Not affiliated with, endorsed by or sponsored by any certification vendor or exam body. Certification names, exam codes and product names are trademarks of their respective owners and are used only to identify the exam a practice product prepares for. Our questions are original and are not actual exam questions.