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Subject: Re: [boost] Mangled "From" field in mailing list posts
From: Vladimir Prus (vladimir.prus_at_[hidden])
Date: 2017-06-14 06:22:14

On 13/06/2017 14:59, Olaf van der Spek via Boost wrote:
> On Tue, Jun 13, 2017 at 10:22 AM, Vladimir Prus via Boost
> <boost_at_[hidden]> wrote:
>> thanks for the explanation. So, if I understand correctly, the problem
>> is that some *senders* have their domains configured to ask recipients
>> to reject emails that don't pass DKIM or SPF? In other words, the question
>> is not how many organizations have DMARC for inbound authentication, but how
>> many users are sending emails to a mailing list
>> (which, by definition, forwards email with modifications) while also
>> requesting than any forwared with modifications emails are rejected by
>> recipients? How many such sending users/domains do we have?
>> I personally think it would be reasonable to just require that posters
>> don't use such domain configuration.
> Doesn't gmail also use dmarc?

It does, as can be seen at

But that configuration (p=none) asks recipient servers to report back to
gmail about any problems they see, not drop email, whereas some
other email providers have "p=reject".

>> If that's not possible, can't we make Mailman not add any footers, and
>> don't add any DKIM signature of its own. Maybe, that will cause original
>> DKIM signature to remain valid and DMARC check to pass?
> The original From header is still problematic AFAIK.

It is my understanding that if you don't modify From header and don't
modify body, then DKIM will pass and SPF will fail, and it's enough
for one of the tests to pass.

- Volodya

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