Are there any SMTP servers that support the SMTPUTF8 extension?

Question

RFC 5321 limits email addresses to 7 bit US-ASCII encoding. RFC 6531 (a fairly new spec) allows email addresses in SMTP commands and IMF headers to be encoded in UTF-8. This SMTP extension makes internationalized email addresses (e.g., pelé@example.com) possible.

An SMTP server advertises support for internationalized email by replying to the EHLO command with the SMTPUTF8 keyword:

250-smtp.example.com at your service
250 SMTPUTF8

An SMTP client utilizes this extension with the MAIL command:

MAIL FROM:<pelé@example.com> SMTPUTF8

Question: Are there any SMTP servers or email clients that support SMTPUTF8?

Not according to [WikiPedia](http://en.wikipedia.org/wiki/Extended_SMTP#List_of_supporting_clients). — Ladadadada, Jan 17 '13 at 13:16
The hold is not appropriate. Read the question. It's not a request for a recommendation. It's asking for the state of the art. — james.garriss, Sep 03 '14 at 19:43
LOL. Earned a silver badge for a Notable Question, yet it was closed as off-topic. — james.garriss, Jul 05 '17 at 11:08

score 3 · Accepted Answer · answered Sep 03 '14 at 12:09

3

Postfix supports a subset of SMTPUTF8 since version 2.12: http://www.postfix.org/SMTPUTF8_README.html

answered Sep 03 '14 at 12:09

mss

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james.garriss · Answer 2 · 2014-09-03T19:41:30.503

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Edit: This answer is no longer true.

As far as I can tell, at this time (Feb 2013) there are no SMTP servers or email clients that support SMTPUTF8.

edited Sep 03 '14 at 19:41

answered Feb 26 '13 at 12:58

james.garriss

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Are there any SMTP servers that support the SMTPUTF8 extension?

2 Answers2