RFC 1870 · INTERNET STANDARD · 1995
WED · 29 JUL 2026
SMTP Service Extension for Message Size Declaration
Overview
RFC 1870, “SMTP Service Extension for Message Size Declaration”, is an Internet Standard document published in November 1995 by J. Klensin, N. Freed, K. Moore. It obsoletes RFC 1653. The canonical text is published by the RFC Editor.
Abstract
This memo defines an extension to the SMTP service whereby an SMTP client and server may interact to give the server an opportunity to decline to accept a message (perhaps temporarily) based on the client's estimate of the message size. [STANDARDS-TRACK]
What “Internet Standard” means
A mature, widely-implemented specification that has completed the full IETF standards process — the highest maturity level on the standards track.
Read this RFC
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Relationships to other RFCs
Other RFCs from 1995
- RFC 1869 SMTP Service Extensions
- RFC 1871 Addendum to RFC 1602 -- Variance Procedure
- RFC 1868 ARP Extension - UNARP
- RFC 1872 The MIME Multipart/Related Content-type
- RFC 1867 Form-based File Upload in HTML
- RFC 1873 Message/External-Body Content-ID Access Type
- RFC 1866 Hypertext Markup Language - 2.0
- RFC 1874 SGML Media Types