Hi Philipp,

You mean because of the fact that more mails might classified as SPAM on our host?

If that's your worry, I can say that that's not the impact of this setting: the "quarantine" value is read from DNS by hosts processing mail claiming to originate from the @common-lisp.net domain. These processors establish the authenticity of the mail through SPF and DKIM. If the authenticity test fails, the current setting ("none") has no effect on mail delivery. The proposed value ("quarantine") does have effect on mail delivery: the value requests to separate from the regular mail flow. Most mail providers do this by sending those mails straight to SPAM.

Either way, we will receive reports from the big mail processing companies (fastmail, zoho, microsoft, google, ...) describing what they did with mail flow coming from @common-lisp.net. There are applications to process these mails to have (visual) integrated reports; we don't have that software in place at the moment. It would be nice to process the individual reports into a visualization like that. Maybe that's something someone else can work on.