RFC 3834 / START HERE
Automatic email replies, before the details
Automatic responses to electronic mail
An automatic responder is software that sends a message after receiving email. RFC 3834 explains how vacation notices and other responders should behave. Its name is a description, not an acronym.
The idea in one picture
Check whether a reply helps
Use the transport return address
Mark and limit the response
A simplified picture of the idea; the chapters explain the actual mechanisms.
Why it exists
An unchecked reply can trigger another robot, reach an unwanted mailing list, or amplify spam. The guide separates the transport return address from human reply fields and explains why a responder sometimes stays quiet.
A familiar example
Nia enables a vacation notice. Her responder checks an incoming message, considers one brief reply to its return address, marks the reply as automated, and limits repeated notices. That reply is not proof Nia read the message.
Helpful background
You can start here without reading another RFC. If these ideas are unfamiliar, these short introductions may help.
What you’ll learn next
Begin with chapter one, or choose a topic.
- Know whose responder is actingA responder is software that sends mail after receiving mail. Personal, Service and Group Responders serve different purposes.→
- Stop replies that would feed a loopReceiving a message does not automatically justify sending one back. Check why a response would be useful before creating it.→
- Choose the return path, not reply-allFor ordinary Personal and Group responses, the transport return address is the recommended destination, rather than the fields used for human conversation.→
- Mark what generated the messageAuto-Submitted describes whether mail came from a human, an automatic generator, or a direct automatic reply. It is not a security credential.→
- Bound the reply and repeat rateThe reply has its own message headers, transport envelope and content. Limits reduce loops, amplification and unintended disclosure.→
- Read the Sieve notification updateRFC 5436 updates the Auto-Submitted extension mechanism and defines a distinct Sieve mailto notification profile.→
This introduction explains RFC 3834 (2004). Read the original RFC ↗