Return Path Blocklist (RPBL)
The Return Path Blocklist (RPBL) from Validity is a list of IP addresses that have been tagged due to spam-like content or behavior. This blocklist is widely used across the industry and based on data from Validity’s robust data sources and cooperative industry partnerships. Mailbox providers, security companies, and spam filtering agencies use this blocklist to make important decisions about blocking and spam filtering.
There are four main criteria for an RPBL listing:
- Botnet Transmission Behavior: machine operating sender
- No authentication: IPs transmitting messages that are lacking/failing SPF and DKIM
- Suspicious attachments: IPs sending messages with potentially malicious attachments
- Pristine trap hits: IPs with messages hitting pristine traps