[Rspamd-Users] remove smtp.auth from header without breaking dkim

[Ralph Seichter]

* L. Jankok:

> In the "ARC-Authentication-Results:" header I want
> "smtp.auth=username at domain" removed for security reasons, but without
> breaking dkim signing for authenticated users.

You can have Postfix strip headers during the submission cleanup phase,
before DKIM signing happens (see "cleanup_service_name").

-Ralph