Ran into this problem setting up a new mailing list system. I'd always wondered by mailing list mail sent from yahoo went directly to spam, while mail from gmai

Ran into this problem setting up a new mailing list system. I'd always wondered by mailing list mail sent from yahoo went directly to spam, while mail from gmail worked just fine. Mailing list mail will always fail DMARC if you keep the original sender's address, but when setting up DMARC for a domain, you specify what should happen to mail from your domain if it fails the DMARC check. For gmail and other sane providers, their DMARC failure is set to ignore, which means DMARC failing for those addresses gets calculated into spam probability, but isn't an auto-fail. For yahoo and AOL, they have it set to reject, which means mailing list mail from those domains automatically goes to spam for gmail. Groupserver mailing list software resolves this by checking the DMARC settings for the sender. If DMARC is set to ignore, the sender address is kept, because it won't actually affect delivery. If it's set to reject, it mangles the sender address so that the mail at least gets delivered.