Queues, retries & timeouts
08A sender keeps undelivered mail with its envelope, delays retries, and uses stage-specific timeouts.
Related RFCs and changes
“Updates” changes part of an earlier RFC. “Obsoletes” replaces it. This list shows selected related documents.
DIAGRAM§ 4.5.4.1 ↗
RFC 5321 · § 4.5.4.1EXAMPLE
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04
Try again within policy.
Delivery resumes or eventually reaches the configured give-up policy.
Protocol participantThreat or exceptionProtocol controlSimplified drawings · precise section references
Read the updated RFC section ↗
Persist first; retry with restraint.
- Mail that cannot be transmitted immediately must be queued and retried periodically.
- After failure, delay retrying that destination; the general recommendation is at least 30 minutes, with more adaptive strategies possible.
- Give-up time generally needs to be at least 4–5 days; retry parameters must be configurable.
§4.5.3 specifies line sizes, minimum supported capacities, and command-specific timeouts. Message content support must be at least 64K octets; that is a minimum capability, not a universal maximum message size.
Read the RFC section ↗Diagrams simplify the RFC. Read the linked sections for complete requirements.
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