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The SMTPUTF8 Extension

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yapadu View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote yapadu Quote  Post ReplyReply Direct Link To This Post Topic: The SMTPUTF8 Extension
    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[]

Wondering if this is a problem with the sender or if SpamFilter does not have this extension supported?
I am a user of SF, not an employee. Use any advice offered at your own risk.
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LogSat View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote LogSat Quote  Post ReplyReply Direct Link To This Post 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 or 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 25
220 iCloud SMTP - 3.4.7 (2007B190-1b2e0e453944)
250-SIZE 28311552
221 2.0.0 Bye
Roberto Franceschetti

LogSat Software

Spam Filter ISP
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