IP-based Reverse Address Validation (IP-Rev)

IP-Rev is a basic authentication and validation mechanism. An IP reverse lookup simply confirms your server has properly configured DNS records, where the DNS A Record and DNS PTR Record match. For most organizations, the DNS PTR Record is managed by their ISP. So it is more difficult for spammers automate the generation and configuration of these records. For spam campaigns using disposable domains the A and PTR records generally do not match.

It is a best practice to ensure your DNS A, PTR and the configured hostname on your mail server all match.

See also..

• E-mail Authentication
• Sender Policy Framework (SPF)
• DomainKeys Identified Mail (DKIM)
• Domain-based Message Authentication, Reporting, and Conformance (DMARC)