RFC 3848 · DRAFT STANDARD · 2004
WED · 29 JUL 2026
ESMTP and LMTP Transmission Types Registration
Overview
RFC 3848, “ESMTP and LMTP Transmission Types Registration”, is a Draft Standard document published in July 2004 by C. Newman. The canonical text is published by the RFC Editor.
Abstract
This registers seven new mail transmission types (ESMTPA, ESMTPS, ESMTPSA, LMTP, LMTPA, LMTPS, LMTPSA) for use in the "with" clause of a Received header in an Internet message. [STANDARDS-TRACK]
What “Draft Standard” means
A historical maturity level (retired in 2011) that sat between Proposed Standard and Internet Standard and required multiple interoperable implementations.
Read this RFC
The canonical text of RFC 3848 is hosted at rfc-editor.org. Available in TXT,HTML.
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