A New Spin on Data: The Return Path Blocklist

One of the many benefits of being part of Return Path is our ability to leverage data sources and analytics to create offerings that benefit the entire email ecosystem. This week, we are excited to be doing just that.

We are rolling out our latest contribution to email safety, the Return Path Blocklist (RPBL). Our intention is to benefit the email ecosystem by combining multiple data sources to create a new blocklist that leverages robust data and state of the art technology. This blocklist focuses on identifying senders with spam-like and abusive behaviors, including:

  • Exhibiting abusive behaviors (botnet traffic, malware, etc)
  • Authentication failures
  • Repeatedly hitting global mailbox provider spam traps
  • Low sender reputation

Return Path has offered a blocklist for some time as a way to benefit the email ecosystem. The new RPBL gives us a chance to expand the data sources being used in the Return Path generated lists, while also updating the underlying technology and data models.

When talking about the new blocklist, there are two main questions that repeatedly emerge:

  • Why is this a Blocklist when the legacy product was a Blacklist? Is that a typo?
  • Why add reason codes to the RPBL?

Blocklist vs Blacklist
When we started development on this new feed, it was clear that the industry had shifted toward using the term blocklist over blacklist. All the major players in the space offer blocklists. While marketers still primarily use blacklist, blacklisted, or blacklisting to describe the action of having IP addresses flagged by a blocklist, the list providers themselves use the term blocklist for the list itself. Providers like Return Path and Spamhaus offer blocklists to Mailbox Providers to aid in their filtering decisions. When a mailbox provider uses a blocklist to determine that the IP addresses should be blocked at the gateway, the action they are taking is blacklisting.

Reason codes
A major part of this work was rebuilding the underlying technology and model used to identify bad actors. In updating the technology, this gave us a chance to add more context on why an IP address was listed. This is important transparency that gives mailbox providers more control on how they use our list plus more insight for listed senders who wish to improve. If you look up why an IP address is listed, we will tell you which of the criteria were flagged.

The Return Path Blocklist is another way that we at Return Path show our dedication to innovation and safety across the email ecosystem. We are excited for this release and encourage you to check the status of your IP addresses and learn more about it here.


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