RFC 6152 · INTERNET STANDARD · 2011
WED · 29 JUL 2026
SMTP Service Extension for 8-bit MIME Transport
Overview
RFC 6152, “SMTP Service Extension for 8-bit MIME Transport”, is an Internet Standard document published in March 2011 by J. Klensin, N. Freed, M. Rose, D. Crocker. It obsoletes RFC 1652. The canonical text is published by the RFC Editor.
Abstract
This memo defines an extension to the SMTP service whereby an SMTP content body consisting of text containing octets outside of the US-ASCII octet range (hex 00-7F) may be relayed using SMTP. [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
The canonical text of RFC 6152 is hosted at rfc-editor.org. Available in TXT,HTML.
Relationships to other RFCs
Other RFCs from 2011
- RFC 6151 Updated Security Considerations for the MD5 Message-Digest and the HMAC-MD5 Algorithms
- RFC 6153 DHCPv4 and DHCPv6 Options for Access Network Discovery and Selection Function Discovery
- RFC 6150 MD4 to Historic Status
- RFC 6154 IMAP LIST Extension for Special-Use Mailboxes
- RFC 6149 MD2 to Historic Status
- RFC 6155 Use of Device Identity in HTTP-Enabled Location Delivery
- RFC 6148 DHCPv4 Lease Query by Relay Agent Remote ID
- RFC 6156 Traversal Using Relays around NAT Extension for IPv6