Hannah, The concern is not what the spec says. It is what implementations build from chain depth data once it is available. Spam filters and reputation systems use available signals regardless of whether a BCP tells them to. A chain with depth 1 is a different feature value than a chain with depth n>1, and systems will train on that difference. The guidance exists so they do not infer more meaning than is intended. This is to address human factors concern.
William From: Hannah Stern <[email protected]> To: <[email protected]> Date: Wed, 14 Oct 2026 07:39:21 -0600 Subject: [Ietf-dkim] Re: BCP: operator note on header size limits and Message-Instance growth > Hi! > > On 10/13/26 20:25, Vittorio wrote: > > [...] > > a receiver may not reject a message on the ground that its chain > > begins at i=1. > > Seems trivial for me. _All_ chains start at i=1. Why mention that at all? > > Hannah. > > -- > Hannah Stern > > Software Developer > Mail Transfer Development > > 1&1 Mail & Media Development & Technology GmbH | | | > Phone: +49 721 91374-4519 > E-Mail: [email protected] | Web: www.mail-and-media.com www.gmx.net > www.web.de www.mail.com www.united-internet-media.de > > Hauptsitz Montabaur, Amtsgericht Montabaur, HRB 5452 > > Geschäftsführer: Alexander Charles, Dr. Michael Hagenau, Thomas Ludwig, Dr. > Verena Patzelt > > > Member of United Internet > > Diese E-Mail kann vertrauliche und/oder gesetzlich geschützte Informationen > enthalten. Wenn Sie nicht der bestimmungsgemäße Adressat sind oder diese > E-Mail irrtümlich erhalten haben, unterrichten Sie bitte den Absender und > vernichten Sie diese E-Mail. Anderen als dem bestimmungsgemäßen Adressaten > ist untersagt, diese E-Mail zu speichern, weiterzuleiten oder ihren Inhalt > auf welche Weise auch immer zu verwenden. > > This e-mail may contain confidential and/or privileged information. If you > are not the intended recipient of this e-mail, you are hereby notified that > saving, distribution or use of the content of this e-mail in any way is > prohibited. If you have received this e-mail in error, please notify the > sender and delete the e-mail. > > _______________________________________________ > Ietf-dkim mailing list -- [email protected] > To unsubscribe send an email to [email protected] > _______________________________________________ Ietf-dkim mailing list -- [email protected] To unsubscribe send an email to [email protected]
