How do filters combine IP, domain, and content reputation?

Modern spam filters use layered evaluation:

IP reputation provides the first signal. Is this sending infrastructure trustworthy?

Domain reputation adds sender identity context. Is this domain associated with good sending practices?

Content reputation evaluates the message itself. Does it contain spam indicators?

These signals feed into weighted scoring models. A bad IP can sink good content. Good domain reputation can survive minor content issues. The weights vary by provider and adapt over time.

The inspector checks the ship (IP), the flag it flies (domain), and the cargo manifest (content). All three contribute to the final assessment.