What’s the role of authentication in placement?

Authentication is the foundation of placement:

SPF: Proves your sending IPs are authorized. Failing SPF raises immediate suspicion.

DKIM: Proves message integrity and sender identity. Missing or failing DKIM is a red flag.

DMARC: Ties SPF and DKIM together with policy. Required by major providers for bulk senders.

Authentication passing is necessary but not sufficient. You can have perfect auth and still spam due to poor reputation or content.

Without authentication, you start at a disadvantage. It is table stakes.

Authentication is your ship's registration papers. Without them, you will not even get past the harbor gate.