Spam Filter ISP Forums : The SMTPUTF8 Extension https://www.logsat.com/spamfilter/forums/ Mon, 18 May 2026 23:38:24 +0000 Thu, 28 Jan 2021 18:37:54 +0000 http://blogs.law.harvard.edu/tech/rss Web Wiz Forums 11.04 360 https://www.logsat.com/spamfilter/forums/RSS_post_feed.asp?TID=7171 <![CDATA[Spam Filter ISP Forums]]> https://www.logsat.com/spamfilter/forums/forum_images/web_wiz_forums.png https://www.logsat.com/spamfilter/forums/ <![CDATA[The SMTPUTF8 Extension : Thanks for the clarification. ]]> https://www.logsat.com/spamfilter/forums/forum_posts.asp?TID=7171&PID=14956&title=the-smtputf8-extension#14956 Author: yapadu
Subject: 7171
Posted: 28 January 2021 at 6:37pm

Thanks for the clarification.]]> Thu, 28 Jan 2021 18:37:54 +0000 https://www.logsat.com/spamfilter/forums/forum_posts.asp?TID=7171&PID=14956&title=the-smtputf8-extension#14956 <![CDATA[The SMTPUTF8 Extension : Hi yapadu,SpamFilter does not...]]> https://www.logsat.com/spamfilter/forums/forum_posts.asp?TID=7171&PID=14955&title=the-smtputf8-extension#14955 Author: LogSat
Subject: 7171
Posted: 02 January 2021 at 11:10am

Hi yapadu,

SpamFilter does not support the SMTPUTF8 extension, and there are no plans to add it. The inability to send an email unless that extension is available is a problem with the sender. They would for example be unable to send emails to any @mac.com or @icloud.com Apple users, since Apple's mail servers do not support that extension either (if they did, "SMTPUTF8" would appear in the EHLO response):

nc -G 1 mx01.mail.icloud.com 25
220 iCloud SMTP - st11p00im-smtpin010.me.com 3.4.7 (2007B190-1b2e0e453944)
ehlo test.logsat.com
250-st11p00im-smtpin010.me.com
250-PIPELINING
250-SIZE 28311552
250-ETRN
250-STARTTLS
250-ENHANCEDSTATUSCODES
250-8BITMIME
250-DSN
250 CHUNKING
quit
221 2.0.0 Bye
]]> Sat, 02 Jan 2021 11:10:11 +0000 https://www.logsat.com/spamfilter/forums/forum_posts.asp?TID=7171&PID=14955&title=the-smtputf8-extension#14955 <![CDATA[The SMTPUTF8 Extension : Does Spam Filter supportthe SMTPUTF8...]]> https://www.logsat.com/spamfilter/forums/forum_posts.asp?TID=7171&PID=14954&title=the-smtputf8-extension#14954 Author: yapadu
Subject: 7171
Posted: 31 December 2020 at 10:01am

Does Spam Filter support the SMTPUTF8 extension?

I have never heard of this extension before myself, but am having one domain that claims they can't receive mail from a specific sender.  The sender's server is reporting the following error:

SMTPUTF8 is required, but was not offered by host myhost.example.com[1.2.3.4]


Wondering if this is a problem with the sender or if SpamFilter does not have this extension supported?
]]> Thu, 31 Dec 2020 10:01:38 +0000 https://www.logsat.com/spamfilter/forums/forum_posts.asp?TID=7171&PID=14954&title=the-smtputf8-extension#14954