Implement ARC signing of e-mail / help wanted

Hi,


The common-lisp.net domain is getting bounces from GMail that the
reputation of our domain is too low to accept some messages.

Apparently, GMail wants mail forwarded by a host to be ARC-signed (
http://arc-spec.org/) in addition to having it DKIM signed by the original
domain.

Since our setup has multiple functions, mail forwarding is handled by
different parts of the mail system setup. In relation to ARC-signing, we:

* Forward mail for users with *@common-lisp.net mail addresses (directly by
Exim4)
* Handle mail for common-lisp.net mailing lists (using mailman)

Does anybody have experience setting up a system like this? Questions that
need to be answered, I think:

* Can we set up ARC signing on the exim4 outbound level (so that we have
ARC signing only once, both for the mailing lists and forwarded mail?
* Does every step in the mail chain on the host need to implement ARC
signing (i.e. Mailman level *and* the mail service responsible for managing
the mail queue)?
* How to implement ARC signing for forwarded mail on exim4 on Debian, since
the exim4 instance (version 4.96) only supports DKIM signing, not ARC
signing...

Any thoughts? Experiences to be shared?

Regards,

-- 
Bye,

Erik.

http://efficito.com -- Hosted accounting and ERP.
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