Check a datagram’s integrity
04The UDP checksum includes a pseudo-header from IP, the UDP header, and the data.
Related RFCs and changes
“Updates” changes part of an earlier RFC. “Obsoletes” replaces it. This list shows selected related documents.
DIAGRAMFields ↗
RFC 768 · FieldsEXAMPLE
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03
A receiver detects a changed covered byte; this is not authentication.
A receiver detects a changed covered byte; this is not authentication.
Protocol participantThreat or exceptionProtocol controlSimplified drawings · precise section references
RFC 768 · IPv4 contextRFC 8200 § 8.1 · IPv6
IPv6 generally requires UDP checksums and uses an IPv6 pseudo-header; do not carry the original IPv4 zero-checksum rule into ordinary IPv6 UDP.
Read the updated RFC section ↗The pseudo-header binds source, destination, protocol, and UDP length into error detection.
- The pseudo-header binds source, destination, protocol, and UDP length into error detection.
- A zero transmitted checksum in the original IPv4 context means no checksum; a computed zero is sent as all ones.
The drawing is a simplified worked example. Follow the linked RFC and its updates for implementation requirements.
Read the RFC section ↗Diagrams simplify the RFC. Read the linked sections for complete requirements.
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