Why is DNS caching important?

• A. Increases DNS query traffic by forcing remote lookups.
• B. Eliminates the need for DNS servers.
• C. Reduces latency and DNS query traffic by storing recently resolved names locally.
• D. Only caches NXDOMAIN responses.

Answer: (C)

Caching DNS responses stores recently resolved domain names and their IP addresses so future requests can be answered quickly without repeating the full lookup. When a client asks for a domain, the resolver first checks its local cache. If the entry is still valid, the response is returned right away, cutting latency because there’s no extra network round-trip to upstream DNS servers. This also lowers overall DNS query traffic since repeated requests for the same domain don’t have to reach remote servers each time. Each cached entry has a time-to-live value that governs how long it stays valid; once it expires, a new lookup is performed to refresh the information. While caches may store negative results in some cases, the main benefit is speeding up responses and reducing network load by keeping valid resolutions locally.