How to Route DMARC Aggregate Reports to a Third-Party S

Why Direct Email Delivery for DMARC Reports Is Problematic

When you set rua=mailto:reports@example.com, receiving mail servers deliver the aggregate report directly to that address. That's a direct connection from the public internet to your mailbox server - and it brings several complications:

Spam filters. Aggregate reports are XML attachments. Some filters flag them as suspicious. Large reports from high-volume senders can trigger quarantine or rejection.

Attachment handling. Some mail systems strip XML attachments or block them entirely. A report that never reaches your inbox is worse than no report at all.

Mailbox management. DMARC reports come daily from every major receiver. At volume, they're large and frequent. Your mailbox needs enough storage, and someone needs to manage the traffic.

Firewall and transport rules. Corporate mail environments often block external MTA connections or apply aggressive transport rules to mailto: addresses. If your security team didn't explicitly allow port 25 from mxsrvc.google.com, your reports may never arrive.

Security. Direct internet-to-mailbox delivery means your monitoring inbox is publicly addressable. If it gets compromised, an attacker has a feed of your sending infrastructure.

None of these problems are unsolvable. But they're all solved better by routing reports through a service that accepts them over HTTP - not directly into a human-accessible mailbox.