"Ernesto Baschny" <ernst(_at_)baschny(_dot_)de> writes:
SMTP response messages should be in plain english (where 7bit is enough),
because this is what every sys-admin is meant to understand. If I send
a message to a friend in France, I don't want to receive a french reply
back, because I wouldn't understand it.
But the SPF 550 messages are not intended for the sys-admin, but for
the end-user who sent the mail to inform that it was not delivered
and why. Therefore, ideally it should be in the same language as the
rejected email - but I suspect that it would be impossible (unless
the sending MUA has included, as some web based MUAs do, an
'X-accept-language' or similar header) to determine the language of
the rejected email and return the reject message in that language.