Missing names & failures
08A nonexistent name, a name without the requested type, and a temporary lookup failure communicate different things.
Terms in this drawing
Related RFCs and changes
“Updates” changes part of an earlier RFC. “Obsoletes” replaces it. This list shows selected related documents.
DIAGRAM§ 5.2.3 ↗
RFC 1034 · § 5.2.3EXAMPLE
4 / 4
04
Remember absence for a bounded time.
Modern negative-cache rules come from RFC 2308, not just the original optional design.
Protocol participantThreat or exceptionProtocol controlSimplified drawings · precise section references
RFC 1034 § 4.3.4RFC 2308 § 5
RFC 2308 specifies negative caching more precisely; its TTL is the smaller of the SOA TTL and SOA MINIMUM.
Read the updated RFC section ↗Do not turn uncertainty into absence.
- A name error means the queried name does not exist.
- An existing name can lack the requested record type without being a name error.
- Temporary failures should be reported separately and not treated as proof of nonexistence.
RFC 1034 originally describes negative caching as optional. RFC 2308 substantially revises those rules; use the later specification for modern implementations.
Read the RFC section ↗Diagrams simplify the RFC. Read the linked sections for complete requirements.
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