The Return Path Blocklist uses data sources from our partners and state of the art technology to identify IP addresses exhibiting characteristics of spam.
When your IP is listed on the Return Path Blocklist, it does not mean that Return Path is blocking your email. The decision to filter or block your email is made by spam filter companies, security vendors and mailbox providers based on their spam filter rules. The Return Path Blocklist is used as one of the many data points in their spam filter.
Listing reason codes
When you look up your IP address, a reason code is returned with a notation indicating the listing reasons:
- 127.0.0.2noauth
- 127.0.0.4pristine
- 127.0.0.6pristine+noauth
- 127.0.0.8suspect_attach
- 127.0.0.10suspect_attach+noauth
- 127.0.0.12suspect_attach+pristine
- 127.0.0.14suspect_attach+pristine+noauth
Fixing the cause and delisting
If your IP is listed, the lookup result page displays a delist button you can use to delist your IP address. After delisting, you have seven days to fix the cause of the listing. If you do not fix the cause of the listing, your IP will be listed again. Continue reading for tips on fixing the cause of each listing reason.
- Authentication Fail (noauth):
- What does this mean?
- Messages from the listed IP address are lacking or failing SPF or DKIM email authentication. Email authentication is a key component of email safety.
- How do I fix it?
- Check with your email administrator or email service provider to make sure you are authenticating all email with SPF and DKIM. Most email service providers set up authentication automatically when you sign up for their service.
- If you are already authenticating your email with SPF and DKIM, check if they are failing verification in the Return Path Platform by looking at the email header detail for Gmail, Microsoft or Yahoo!.
- Check with your email administrator or email service provider to make sure you are authenticating all email with SPF and DKIM. Most email service providers set up authentication automatically when you sign up for their service.
- What does this mean?
- Pristine Spam Traps (pristine):
- What does this mean?
- Messages from the listed IP address are being sent to pristine spam traps. Pristine spam traps have never signed up with any email program and are usually acquired through a list purchase or list harvesting technique.
- How do I fix it?
- Perform an audit on all of your list acquisition methods. If you discover that email addresses were purchased or scraped from a social network like Facebook or LinkedIn, immediately stop sending to those email addresses.
- Run your email list through a list verification service. While a list verification service doesn't identify spam traps, it does help identify malformed and misspelled addresses that may be used as a spam trap.
- Have a strategy in place to regularly suppress subscribers that no longer engage with your email. Most spam traps do not engage with your email, so you can prioritize suppressing subscribers that have never engaged with your email after a period of time that makes sense for your business.
- If you continue having a problem with sending to pristine spam traps after taking the steps above, you may want to use a confirmed opt-in permission method when acquiring new addresses.
- What does this mean?
- Suspicious Attachments (suspect_attach):
- What does this mean?
- Messages from the listed IP address have been flagged as suspicious based on message content patterns and file types known to carry malware.
- Common file types used for distributing malware include those listed below, but any file type may be used.
- Executable: .exe
- Java Script: .js and .jar
- VB Script: .vb and .vbs
- Microsoft Office: .doc, .docx, .docm
- How do I fix it?
- Contact your IT department or Security Operations team.
- Ensure there are no unauthorized third parties accessing your system to send spam or malware with an attachment.
- Ensure all inbound and outbound email and attachments are scanned for viruses and malware.
- Use the PCMAG.com vendor list if you need to purchase software.
- Do not send attachments with bulk email sends as they are usually perceived as spam. Bulk email sends may be for marketing purposes or a mass distribution send from a sales representative to their contact list.
- If you want your subscribers to get access to a coupon, insert the coupon as an image they can print from their email. If you want them to fill out a form, direct them to your website.
- Contact your IT department or Security Operations team.
- What does this mean?
