If you're running a mailing list that retains the original DKIM signatures [that will fail because the message subject and body have been modified] you might want to strip/hide them because it can cause Apple iCloud Mail to increment the spam score by 1 which can cause it to be delivered to Junk (despite "I've pretty religiously been marking each email as not spam but it's not keen at all").
For an email originating from gmail.com retaining the original From:, it doesn't appear to care about the DMARC failure (p=none) but it doesn't like the failed DKIM signature. There was also a signed ARC result (from before the email reaches Mailman) that would be invalid but hiding that didn't have any visible effect on the score. There's no forwarding involved, the user is subscribed directly with an address hosted by iCloud. X-ICL-SCORE: 4.332033240044 X-Apple-MoveToFolder: Junk x-spam-flag: yes x-suspected-spam: true ... Authentication-Results: bimi.icloud.com; bimi=skipped reason="insufficient dmarc" X-ARC-Info: policy=fail; arc=fail; id=mx5.messagingengine.com Authentication-Results: arc.icloud.com; arc=fail Authentication-Results: dmarc.icloud.com; dmarc=fail header.from=gmail.com X-DMARC-Info: pass=fail; dmarc-policy=none; s=r0; d=r0; pdomain=gmail.com X-DMARC-Policy: v=DMARC1; p=none; sp=quarantine; rua=mailto:mailauth-repo...@google.com Authentication-Results: dkim-verifier.icloud.com; dkim=pass (1024-bit key) header.d=lists.example.com header.i=@lists.example.com header.b=soRHKGr8 Authentication-Results: dkim-verifier.icloud.com; dkim=fail reason="signature verification failed" (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b=rcro5QTc Authentication-Results: spf.icloud.com; spf=pass ... ... From: Example <exam...@gmail.com> X-ICL-SCORE: 3.333033230041 X-Apple-MoveToFolder: INBOX ... Authentication-Results: bimi.icloud.com; bimi=skipped reason="insufficient dmarc" X-ARC-Info: policy=fail; arc=none Authentication-Results: arc.icloud.com; arc=none Authentication-Results: dmarc.icloud.com; dmarc=fail header.from=gmail.com X-DMARC-Info: pass=fail; dmarc-policy=none; s=r0; d=r0; pdomain=gmail.com X-DMARC-Policy: v=DMARC1; p=none; sp=quarantine; rua=mailto:mailauth-repo...@google.com Authentication-Results: dkim-verifier.icloud.com; dkim=pass (1024-bit key) header.d=lists.example.com header.i=@lists.example.com header.b=iMjTZqEm Authentication-Results: spf.icloud.com; spf=pass ... ... From: Example <exam...@gmail.com> -- Simon Arlott _______________________________________________ mailop mailing list mailop@mailop.org https://list.mailop.org/listinfo/mailop