How does rDNS mapping confirm sender identity?

rDNS serves as identity verification:

What it proves:

The IP owner configured a deliberate mail server name

There is infrastructure investment (not a random compromised machine)

The operator expects to be identified by this hostname

What it does not prove:

The sender is authorized to use a specific From domain (that is SPF/DKIM)

The message content is legitimate (that is reputation)

Identity chain:

PTR says "this IP calls itself mail.tidalmail.com"

A record confirms "mail.tidalmail.com is this IP"

Consistency suggests legitimate, intentional configuration.

The ship declares its name. The registry confirms that name is registered to that hull. Identity verified at the infrastructure level.