Build a DMARC record that tells receivers what to do with spoofed mail — and read the reports that prove it's working.
v=DMARC1; p=quarantine;
p=quarantine or p=reject — p=none won't show your logo.rua is how you learn. Without aggregate reports you're flying blind — point it at a mailbox or a DMARC report service.adkim=s; aspf=s) breaks most third-party senders — stay relaxed unless you control every sender.pct below 100 with p=reject is a safe way to ramp up enforcement.DNS lookups run from your browser via DNS-over-HTTPS. Nothing is uploaded.