What is the relationship between forward zones and cache behavior?

• A. Forwarding can be combined with caching
• B. Forward zones disable caching
• C. Forward zones only cache results from forwarders
• D. Forward zones require real-time queries to root servers

Answer: (A)

Forwarding and caching work together, not against each other. When a DNS server uses forward zones, it sends queries to specified forwarders, but that doesn’t stop the server from storing answers it learns in its own cache. The responses received from forwarders are cached just like responses obtained directly from root or authoritative servers, and each cached entry stays valid for its TTL. As a result, subsequent queries for the same name can be answered quickly from the local cache without repeating the forwarder query, until the TTL expires. This combination reduces repeated forwarding traffic and speeds up responses. The idea that caching is disabled, or that only forwarder results are cached, isn’t correct, and real-time root-server queries aren’t strictly required if a valid cached answer exists.