Packets & sanity checks
05Packet fields describe mode, version, stratum, quality, and timestamps. The peer process rejects unusable or mismatched data.
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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§ 7.3 ↗
RFC 5905 · § 7.3EXAMPLE
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04
Reject an unrelated reply.
A timestamp mismatch prevents this packet from becoming a clock update.
Protocol participantThreat or exceptionProtocol controlSimplified drawings · precise section references
Read the updated RFC section ↗
Check packet context before accepting timing evidence.
- The origin timestamp must correspond to the request state for the exchange.
- The on-wire checks detect duplicate, replayed, and bogus packets using timestamp state.
- Mode, synchronization state, quality bounds, and any configured authentication are part of acceptance processing.
A checksum detects accidental corruption, not a malicious sender. Timestamp correlation also does not replace cryptographic authentication against an attacker able to observe or modify traffic.
Read the RFC section ↗Diagrams simplify the RFC. Read the linked sections for complete requirements.
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