What is the Return Path Blocklist?
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.
What is the intention of the Return Path Blocklist?
The RPBL specifically leverages Validity’s data sources in order to identify corrupt mailings, botnets and malicious spam across the ecosystem. While it’s rare that marketers or legitimate senders land on the list, it can happen. Landing on the blocklist often gives marketers insight into problems that they weren't aware existed. The ultimate purpose of the list is to help mailbox providers block and filter spam. The RPBL is part of Validity’s efforts to make email marketing easier and safer across the entire email ecosystem.
Does landing on the blocklist have a direct impact on my inbox placement rates?
Blocklists do not have a direct impact on deliverability, but are often used to influence blocklisting or filtering decisions. If your IP gets listed, your deliverability may be affected at many mailbox provides. Filtering is at the discretion of the blocklist users.
How can I get off the blocklist?
IP addresses are removed when you solve the cause of listing. You can request an immediate, temporary removal on the RPBL Blocklist Remover page while you investigate and correct the problem. After 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.
Who has access to the blocklist?
Validity provides the list to mailbox providers, email security vendors and filtering companies via Zone File or DNS query at no cost to them. It is important to note that Validity does not control how these companies treat/use blocklists, and each will use the RPBL at their own discretion. The RPBL helps Mailbox Providers and Filtering Companies make policy decisions around bulking and blocklisting.
What are the criteria that can land a sender on the blocklist?
There are five 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
- Sender score: IPs with a sender score of 0 in Everest or at senderscore.org
How do I find the reason for being listed on the RPBL?
After finding the reason that your IP has been listed through the RPBL Blocklist Lookups tool, you will be given access to a classification guide. In this guide, you will a find clear reason for listing. From here, we recommend taking the necessary actions to improve your sending practices.
I was listed on the RPBL because my IP was exhibiting Botnet characteristics. What can I do to fix this?
In this situation, it is possible that you are a bot operator or that the IP is being abused by a botnet. In cases where that sender manages their own infrastructure, the sender should work with their SecOps team to identify and resolve any cases of abuse. For senders using a hosting company or outsourced infrastructure, the sender should talk to that provider.
I was listed on the RPBL because my IP was sending messages containing suspicious or vicious attachments. What can I do to fix this?
If your IP was flagged for sending suspicious attachments, we recommend reviewing email attachments leaving your network. Sending of malicious attachments could indicate account or system compromise, or a legitimate user may be trying to transmit potentially dangerous attachment types. You may need to contact your internal teams to discuss the type of attachment being used or if the attachment is necessary.
I was listed on the RPBL because my IP was sending emails to pristine traps. What can I do to fix this?
If your IP is sending a high volume of messages to pristine traps we recommend reviewing list hygiene practices and following best practices. You can check out our Help Center for recommendations on how to improve your sending and list hygiene practices. Senders may also want to leverage a list verification service like BriteVerify.
I was listed on the RPBL because I have a sender score of 0. What can I do to fix this?
If you have a sender score of 0 in Everest or at senderscore.org, you will be listed for 7 days and then unlisted if your score has improved. To improve your score, we recommend reviewing and following best practices for sender reputation. You can check out our Help Center or senderscore.org/learn for recommendations on how to improve your sender reputation and practices.
I was listed on the RPBL because of an authentication fail. What can I do to fix this?
Completely unauthenticated email leaving your IP address could indicate account or system compromise or a lapse in best practice for legitimate senders. Senders should review their DKIM and SPF and update accordingly. If your ESP manages this for you, we recommend reaching out to them directly.
Will the RPBL affect the blocklist tile in Everest?
When a sender lands on the RPBL, the blocklist tile in Everest will reflect the listing accordingly. The sender will then have to option to select Request Removal from the tile, directing them to the RPBL Blocklist Remover page.
If a Certified IP lands on the Return Path Blocklist, will the IP be suspended in Certification?
If a sender's Certified IP lands on the RPBL, that IP will be fully suspended in Certification.
What best practices can I follow to stay off the RPBL?
There are a number of best practices you can follow to stay off the RPBL:
- 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 have asked 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
I don't have a sender score. Am I at risk of landing on the RPBL?
No. Not having a sender score at all is different from having a sender score of 0.
There are many legitimate reasons a sending IP may not have a sender score. For example, smaller senders may have too low a volume to register a score. Or a sender may be warming up a new IP and not yet have enough sending volume for a sender score. As long as you continue to follow best practices, you should be able to avoid a score of 0.
I'm sending from a list of pooled IPs. How do I know which sender landed us on the blocklist?
We do not currently provide insight into domains because the list is IP-based. However, reputation solutions like Everest will help identify areas of improvement in sending practices. Please contact Validity today for a demo.