Return Path Blocklist (RPBL)


The Return Path Blocklist’s (RPBL) algorithm identifies indicators of spam and abusive behavior from IPs, such as botnets, suspicious payloads, and those failing authentication.

This blocklist is used by mailbox providers, security vendors, and others as an element in their filtering algorithms and policies.The blocklist scores IPs in real time based on volume data, spam traps, and complaint sources.

  • Listings occur at the IP address level.
  • The impact on deliverability is high.
  • The RPBL is used by several mailbox providers based in the U.S. and internationally.

If your IP gets listed, your deliverability may be affected at many mailbox providers. Filtering is at the discretion of list users.

Reasons for getting listed

IP addresses are listed based on evidence of abusive behavior and sending mail that is inappropriate for a mail server.

Examples for getting listed include:

  • Sending to spam traps
  • Sending large volumes of mail to addresses that do not exist
  • Sending email campaigns from botnets
  • Failing email authentication or having email authentication discrepancies

How to get off this blocklist

IP addresses are removed when you resolve the cause of the listing. You can request an immediate, temporary removal on the Return Path website while you investigate and correct the problem.

When you submit a request, we will share with you the underlying reason for your listing. If you don’t resolve the underlying problem, your IP address will likely be listed again.

Tips for staying off this list

  • Use opt-in or confirmed opt-in permission methods for new subscribers
  • Keep complaints low by only sending relevant and engaging email to users that ask to receive it
  • Practice good list hygiene and suppression to avoid spam traps
  • Ensure your IP address has a non-generic, unique reverse DNS (PTR) record
  • Do not send email from a dynamic IP address
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