Chatting with Florian off list it seems likely that the Postfix smarthost is accepting Content-Transfer-Encoding: 8bit messages, DKIM signing them, only then discovering that the recipient MX doesn’t offer 8BITMIME. It rewrites the body using quoted-printable encoding, breaking the signature in the process.
So an MUA sending 8bit mail to a non-8BITMIME recipient may cause the signature to break. Setting force_mime_input_conversion to reencode all 8bit mail on submission looks like a fix, for a signing outbound server anyway. Cheers, Steve > On 21 Oct 2024, at 16:15, Florian Effenberger via mailop <mailop@mailop.org> > wrote: > > > my bad, the above information was not acurate. > > Roundcube, MIME-coding for 8bit characters DISABLED, mail fails > Roundcube, MIME-coding for 8bit characters ENABLED, mail gets through > > However, that both times translates to > Content-Type: text/plain; charset=UTF-8; format=flowed > Content-Transfer-Encoding: quoted-printable > > (I have a similar problem with Thunderbird however.) > > Florian > _______________________________________________ > mailop mailing list > mailop@mailop.org > https://list.mailop.org/listinfo/mailop _______________________________________________ mailop mailing list mailop@mailop.org https://list.mailop.org/listinfo/mailop
