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RFC 8489 / PROTOCOL MECHANISMS

Match a response to its transaction

02

A transaction ID correlates responses with the initiating request.

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DIAGRAM§ 6.3 ↗
RFC 8489 · § 6.3EXAMPLE
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Match a response to its transactionA transaction ID correlates responses with the initiating request.Outstanding request · transaction ID XResponse · transaction ID XResponse · different ID Yignore96-bit correlation value; matching alone is not authentication
03
Ignore a candidate response that does not match an outstanding transaction.

Ignore a candidate response that does not match an outstanding transaction.

Protocol participantThreat or exceptionProtocol controlSimplified drawings · precise section references
KEY POINT

STUN uses a 96-bit transaction ID chosen with the specified unpredictability requirements.

  • STUN uses a 96-bit transaction ID chosen with the specified unpredictability requirements.
  • Retransmitted requests belong to the same transaction; matching alone is not cryptographic authentication.
DETAILS

The drawing is a simplified worked example. Follow the linked RFC and its updates for implementation requirements.

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Privacy
All chapters in this RFC
  1. Learn the server-observed address
  2. Match a response to its transaction
  3. Parse the STUN header and attributes
  4. Use credentials for message integrity
  5. Separate discovery from connectivity and privacy
RFC 9700 / CHAPTERS

Chapters

For full details, tables, algorithms, and exceptions, read the original RFC.

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