SPF, DKIM, DMARC: the 15-minute setup that actually passes

To fix email authentication issues, set up SPF, DKIM, and DMARC in 15 minutes. SPF lists allowed senders, DKIM signs messages, and DMARC sets policy and reports failures. Verify SPF and DKIM with dig or checkers. Create a single SPF record and prune unnecessary includes. Use provider-generated DKIM records and avoid proxying them. Set up DMARC with a TXT record at _dmarc.yourdomain.com.