Summary
The overwhelming consensus from experts, marketers, and documentation is that email senders should not be overly concerned about RFC-Clueless blocklist listings. It is generally considered irrelevant due to its limited use by major ISPs, its tendency to list entire TLDs (leading to false positives), and its overall poor reputation. The emphasis should instead be on maintaining a good sender reputation, following email sending best practices, and focusing on reputable blocklists that are actively used by major email providers, such as Spamhaus. Correlation between being on any blocklist and experiencing delivery issues does not necessarily imply causation, as both can stem from underlying sending behavior. Major email providers like Gmail rely more on their own internal technologies than external lists.
Key findings
- RFC-Clueless: Irrelevant: RFC-Clueless is widely regarded as an irrelevant blocklist with little to no impact on email deliverability for most senders.
- Limited Use by ISPs: Major Internet Service Providers (ISPs) and email providers do not typically use RFC-Clueless for filtering emails.
- False Positives: RFC-Clueless lists entire Top-Level Domains (TLDs), leading to a high risk of false positives if used for email blocking.
- Focus on Reputable Blocklists: Email senders should prioritize monitoring and avoiding listings on reputable and widely-used blocklists like Spamhaus.
- Sender Reputation is Key: Maintaining a good sender reputation through responsible sending practices is more important than worrying about RFC-Clueless.
- Correlation, Not Causation: If experiencing delivery issues and listed on a blocklist, it's crucial to investigate underlying sending practices, as correlation does not equal causation.
- Internal Filtering Systems: Major email providers, like Google, rely heavily on their own internal spam filtering technologies, making external blocklists less influential.
Key considerations
- Sending Best Practices: Adhere to established best practices for email sending, including authentication, relevant content, and respecting recipient preferences.
- Reputation Monitoring: Regularly monitor your sender reputation and presence on reputable blocklists to proactively identify and address potential deliverability issues.
- Investigate Deliverability Issues: When facing deliverability challenges, investigate the root cause of the issues, focusing on sending practices and content, rather than solely blaming blocklist listings.
- Email Authentication: Ensure proper email authentication (SPF, DKIM, DMARC) to improve sender reputation and reduce the likelihood of deliverability problems.
What email marketers say
10 marketer opinions
The consensus from various email marketing experts and community discussions is that RFC-Clueless is not a significant blocklist for email senders. It's generally considered irrelevant as it's not widely used by major ISPs or email providers, and listing entire TLDs can lead to false positives. Focusing on reputable blocklists and maintaining good sending practices is more important for email deliverability.
Key opinions
- Irrelevant Blocklist: RFC-Clueless is generally considered an irrelevant blacklist that doesn't significantly impact email deliverability.
- Not Widely Used: Major ISPs and email providers do not typically use RFC-Clueless for filtering emails.
- False Positives: The list includes entire TLDs, leading to many false positives if used for blocking.
- Focus on Reputable Lists: Email senders should prioritize monitoring and avoiding listing on reputable blocklists like Spamhaus.
Key considerations
- Sending Reputation: Maintain a good sending reputation by following best practices to avoid being listed on more influential blocklists.
- Good Sending Practices: Implement good sending practices to improve email deliverability and avoid deliverability issues in the first place.
- Monitor Key Blocklists: Instead of worrying about RFC-Clueless, monitor your presence on widely-used and influential blocklists.
Marketer view
Email marketer from EmailDeliverability.com shares that RFC-Clueless is not one of the blocklists that are checked by most large mail providers so it is unlikely to impact your email deliverability. It only affects sysadmins that use this list.
16 Apr 2023 - EmailDeliverability.com
Marketer view
Email marketer from StackExchange shares that you can't get off the RFC-Clueless list and that it is pretty useless and you will probably do more harm than good by trying to filter based on it.
7 May 2022 - StackExchange
What the experts say
5 expert opinions
Experts generally agree that RFC-Clueless is not a significant concern for email senders. It is often characterized as a 'grudge list' with limited relevance to actual deliverability issues. The focus should instead be on reputable blocklists like Spamhaus and maintaining good sending practices. While being on any blocklist might correlate with delivery problems, it doesn't necessarily cause them, as detection methods often overlap. It's also noted that major providers like Gmail rely on internal technology more than external blocklists.
Key opinions
- RFC-Clueless Irrelevance: RFC-Clueless is considered a low-priority blocklist with limited impact on email deliverability.
- Focus on Reputable Lists: Email senders should prioritize monitoring and avoiding listing on reputable blocklists that are actively used by major ISPs.
- Correlation vs. Causation: Being on a blocklist and experiencing delivery issues may be correlated but not causally linked; often, both stem from underlying sending behavior.
- Internal Technology: Major email providers like Gmail rely heavily on their own internal spam detection technologies rather than solely depending on external blocklists.
Key considerations
- Sending Practices: Prioritize maintaining good sending practices to avoid being listed on any blocklist, regardless of its perceived influence.
- Reputation Monitoring: Monitor your sending reputation and presence on reputable blocklists to proactively address potential deliverability issues.
- Root Cause Analysis: If experiencing delivery problems, investigate the underlying sending practices and content issues rather than immediately assuming a blocklist is the sole cause.
Expert view
Expert from Email Geeks responds that if you're looking for where you’re listed because you’ve seen a delivery issue, it’s extremely unlikely that the listing caused the issue.
12 Aug 2022 - Email Geeks
Expert view
Expert from Word to the Wise explains that there are many blocklists, but only a few have significant impact on delivery. While they don't specifically address RFC-Clueless, the advice is to focus on reputable lists and good sending practices.
25 Feb 2025 - Word to the Wise
What the documentation says
4 technical articles
Documentation sources suggest that RFC-Clueless is not a significant concern for email senders. RFC-Clueless.org describes its purpose as a tool for sysadmins to block RFC-ignorant hosts. DNSQueries indicates the list has a poor reputation due to listing entire TLDs and recommends against taking it seriously. More broadly, both TalosIntelligence and Google Workspace emphasize the importance of maintaining a good sender reputation and following best practices for email deliverability, implying that a focus on these aspects makes worrying about less influential blocklists unnecessary.
Key findings
- Limited Influence: RFC-Clueless is intended for specific sysadmin use and is not widely adopted or influential in deliverability.
- Poor Reputation: RFC-Clueless has a negative reputation due to its practice of listing entire Top-Level Domains (TLDs).
- Sender Reputation Matters: Maintaining a good sender reputation and following best practices for email deliverability are key and make worrying about less influential blocklists like RFC-Clueless unnecessary.
Key considerations
- Good Sending Practices: Prioritize following established best practices for email sending (authentication, content, frequency, etc.).
- Sender Reputation: Focus on maintaining a positive sender reputation through consistent and responsible email practices.
- Authenticating Email: Properly authenticate your email to improve sender reputation and reduce deliverability issues.
Technical article
Documentation from Google Workspace shares that you should authenticate your email, only send wanted emails and monitor your sending reputation. They don't comment on RFC-Clueless but focusing on your sending reputation will improve your deliverability.
8 Sep 2023 - Google Workspace
Technical article
Documentation from RFC-Clueless.org explains that the list is for sysadmins who wish to block email from hosts violating standards and that adhere to rfc-ignorant practices.
7 May 2023 - RFC-Clueless.org
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