What’s the connection between DNS trust and sender reputation?

DNS as a trust signal:

Positive signals:

Valid PTR with FCrDNS

Proper SPF, DKIM, DMARC

DNSSEC (where checked)

Professional hostnames

Consistent, well-maintained records

Negative signals:

Missing PTR

Generic/residential PTR names

Authentication failures

Inconsistent or broken records

Reputation contribution:

DNS configuration is baseline expectation

Poor DNS = likely not a legitimate sender

Good DNS = passed first test (not sufficient alone)

DNS quality is table stakes for sender reputation.

Proper ship documentation is expected. Missing papers suggest illegitimate operation.