SMTPUTF8 is required, but was not offered by host

wattie

wattie

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Joined
May 31, 2008
Messages
948
Location
Bulgaria
One user is complaining that e-mail sent to a domain on the server was bounced back with the following error:

Code: 
SMTPUTF8 is required, but was not offered by host

What could be the issue?
 
No, my Exim is the receiving system... The sending system is... I don't know what. It's a popular free webmail - abv.bg
 
So your Exim is the bouncing system then. Still... it's a Postfix issue, then the sending system is Postfix.
It needs to fix it to declare it's not using smtputf8 specifically.

They need to change their main.cf from Postfix and either
a) adjust the "compatibility_level" parameter
b) or set/add smtputf8_enable=no

So I would contact the sending system, because as far as I can see, it's caused by a header saying that it supports smtputf8 while in fact it doesn't so Exim refuses it.
 
Thanks. It will be a tough fight as this is a big free webmail provider in Bulgaria...
 
Well if that is a big webmail provider, they will also update their stuff if they got enough complaints about non deliverable mail because of their fault. Or they get smaller when their users switch to Microsoft, Gmail or GMX or kind like.

Maybe (I'm really not sure about this), the smtputf8 support can be disabled in Exim via the allow_utf8_domains = false setting in exim.conf file. However, this might very well cause lots of other domains using smtputf8 to be rejected.

Or maybe smtalk or somebody else has an optional solution.
 
I have a similar issue. Rolling out UTF8 support everywhere is better done sooner rather than later I think. From what I can see, Exim supports SMTPUTF8, so perhaps we'd all be better off if it was enabled in the default Exim config?

Edit: It looks like support for SMTPUTF8 in Dovecot/LMTP is limited at best, so until the entire stack fully supports SMTPUTF8, no solution is ideal. Personally I've opted to not advertise SMTPUTF8 support as early in my own stack as possible, which really just moves the problem. However, I think rejecting a mail outright, is better than bouncing it later.
 
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