I want to TEMPORARILY (I hope) whitelist redac...@mg.pluspora.com as a sender address as long as the mail is being sent by mailgun.us. How would you do it?You could add a check_sender_access which returns OK for mg.pluspora.com before the reject_unknown_sender_domain in smtpd_recipient_restrictions.
s/OK/permit_auth_destination/ reduces the chance to become an open relay for that sender
