Reading email headers
- In Gmail
- Show original
- Look for Authentication results header for dkim, spf, dmarc pass / fail status
- Return-path email domain is used for dmarc spf alignment check
- Dkim sig header is used for dmarc dkim alignment check
- Only 1 of spf or dkim alignment needs to pass for dmarc to pass
- mtasv.net is the mailer domain for postmark