Caches & TTL
06Caching reduces repeated work. A TTL limits how long learned data can be reused without another lookup.
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Related RFCs and changes
“Updates” changes part of an earlier RFC. “Obsoletes” replaces it. This list shows selected related documents.
DIAGRAM§ 3.6 ↗
RFC 1034 · § 3.6EXAMPLE
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04
Check freshness before reuse.
Within the TTL return the cached data; after expiry perform resolution again.
Protocol participantThreat or exceptionProtocol controlSimplified drawings · precise section references
Read the updated RFC section ↗
A cached answer has a deadline.
- TTL is expressed in seconds and controls caching lifetime.
- Authoritative local zone data takes precedence over cached information.
- A zero TTL prevents retention beyond the current transaction.
TTL is not a promise that authoritative data cannot change. Cached answers can remain valid for reuse until their allowed lifetime expires.
Read the RFC section ↗Diagrams simplify the RFC. Read the linked sections for complete requirements.
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