Re: dmarc failure when sending to the list

From: Patrick Proniewski <>
Date: Wed, 9 Jul 2014 22:12:30 +0200

On 07 juil. 2014, at 15:55, Patrick Proniewski wrote:

> On 7 juil. 2014, at 15:39, Scott Kitterman <> wrote:
>>> direct I saw "Content-Transfer-Encoding: quoted-printable"
>>> via opendkim-users I received the message as
>>> "Content-Transfer-Encoding: 8bit"
>>> So the listserver rewrite your message and invalidates your signature.
>> It's better to convert before signing to mitigate the risk of failures due to downstream changes.
> Admitting I could convert before signing, how would I know what is the Content-Transfer-Encoding preferred by the remote server?

Ok, looks like DKIM requires that Content-Transfer-Encoding is 7bits (quoted-printable for example) before signing, according to the RFC: <>
Now the problem remains, unfortunately, meaning that using a strong DMARC/DKIM policy is impossible unless you don't mind seeing your emails beeing dropped by remote mail servers.

Am I missing something?

Received on Wed Jul 09 2014 - 20:12:45 PST

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