Summary
Understanding how to get a sender domain onto SpamAssassin's internal whitelists, specifically for the USER_IN_DEF_DKIM_WL and USER_IN_DEF_SPF_WL rules, can be perplexing for email senders. These whitelists grant a significant advantage by drastically reducing spam scores. However, the process for inclusion is not straightforward, nor is there a public application method. It turns out that a key whitelist file, 60_whitelist_auth.cf, contains the majority of these whitelisted domains, and additions are rare and ad hoc, based on the discretion of SpamAssassin project committers. This highlights the limited influence senders have over these specific internal whitelists.
Key findings
- Significant advantage: Domains on SpamAssassin's internal whitelists (USER_IN_DEF_DKIM_WL and USER_IN_DEF_SPF_WL) receive a substantial negative spam score, making their emails far less likely to be flagged as spam.
- No formal application process: There is no proactive way for email senders to apply for inclusion on these internal SpamAssassin whitelists. Unlike some other reputation services, there's no form-based submission or standard process.
- Ad hoc inclusion: Entries are added very rarely and at the discretion of a SpamAssassin project committer. This happens when a committer identifies a need due to false positives or borderline scoring of messages from a sender known to send legitimate, high-value email (ham).
- Limited scope for major providers: While SpamAssassin is widely used, large mailbox providers often use heavily customized versions or entirely different filtering systems. Therefore, inclusion on these default whitelists may not directly impact deliverability to major ISPs.
- Primary whitelist file: The 60_whitelist_auth.cffile on GitHub contains the primary list of internally whitelisted domains, describing the criteria for their inclusion.
Key considerations
- Focus on fundamental deliverability: Given the difficulty and lack of transparency in getting on these specific SpamAssassin whitelists, email senders should prioritize universal best practices for improving sender reputation across all providers.
- Maintain strong authentication: Ensure proper SPF and DKIM implementation, even if it doesn't guarantee a SpamAssassin whitelist spot. These are crucial for overall deliverability and reducing spam classifications. A good starting point is a simple guide to DMARC, SPF, and DKIM.
- Understand local whitelisting: While global SpamAssassin whitelists are elusive, individual recipients or mail administrators can configure SpamAssassin to whitelist specific senders or domains at a local level. This is often the more practical route for achieving whitelisting with particular targets.
- Monitor blocklists: Regularly check if your IPs or domains are listed on public blocklists (blacklists). Being listed on a major blacklist can significantly harm your deliverability, regardless of SpamAssassin's internal whitelists. For more, see what happens when your domain is on an email blacklist.
What email marketers say
Email marketers often seek any advantage to ensure their messages reach the inbox, and the idea of a SpamAssassin whitelist is certainly appealing. However, the general consensus among marketers suggests that pursuing inclusion on SpamAssassin's default whitelists is not a practical or effective strategy. Their focus typically remains on robust email marketing practices and direct engagement with recipients for local whitelisting.
Key opinions
- Limited value: Many marketers find that the default SpamAssassin rule set, including its whitelists, is not heavily relied upon by major mailbox providers or commercial filtering companies. These entities often implement their own highly customized rules or have moved away from SpamAssassin entirely.
- Focus on custom rule sets: Commercial filters that were once built on the SpamAssassin engine have largely evolved to use their own proprietary rule sets, further diminishing the impact of the default whitelists.
- Local whitelisting is key: The more effective approach for marketers is to encourage individual recipients or their IT administrators to manually whitelist their email address or domain within their own email client or server settings. This directly addresses the recipient's local SpamAssassin configuration if it's in use. Learn more about how to get emails whitelisted.
- Maintaining a clean sender reputation: Marketers emphasize that consistent sending of wanted mail, avoiding spam traps, and adhering to general email best practices are far more impactful than chasing obscure whitelists. This includes understanding why your emails are going to spam.
Key considerations
- Focus on recipient engagement: Encourage subscribers to add your sending address to their contacts or address book. This is a direct and highly effective way to bypass many spam filters, including SpamAssassin's local rules.
- Build strong sender reputation: Prioritize maintaining a positive sender reputation through low complaint rates, high engagement, and strict list hygiene. This is universally beneficial for deliverability.
- Direct admin contact: For specific B2B scenarios, direct communication with the recipient's IT or email administrator to request an IP or domain whitelist (allowlist) can be successful. This is discussed further in how to convince an email network owner to whitelist.
- Technical configuration: Ensure your SPF and DKIM records are correctly configured and pass authentication checks. While not a direct path to a hardcoded SpamAssassin whitelist, these are fundamental for proving sender legitimacy.
Marketer view
Email marketer from Email Geeks observes that SpamAssassin appears to whitelist certain marketing brands, even smaller ones, beyond what is hardcoded in its source. They found a significant number of senders receiving favorable whitelisting scores in their database, raising questions about the criteria for such inclusion.
Marketer view
Email marketer from Stack Overflow advises that to whitelist an address, one should open the SpamAssassin configuration file, typically located at /etc/spamassassin/local.cf. They suggest adding a line like whitelist_from abc@def.com to specifically whitelist the desired email address.
What the experts say
Deliverability experts clarify that the perceived advantages of SpamAssassin's internal whitelists are often overstated, particularly for large-scale email sending. They emphasize that major mailbox providers and commercial anti-spam solutions typically operate with highly customized rulesets, or entirely different systems, making the default SpamAssassin whitelists less relevant than one might assume.
Key opinions
- Limited impact on major providers: Experts strongly assert that large mailbox providers do not generally use the default SpamAssassin rule set. Instead, they develop and implement their own sophisticated filtering rules and algorithms.
- Internal lists for false positive management: SpamAssassin's internal whitelists (def_whitelist_auth) are primarily there to prevent false positive complaints for well-known, high-volume senders, rather than serving as a general mechanism for senders to gain preferential treatment.
- Ad hoc nature of inclusions: Inclusion on these lists is rare, ad hoc, and without a formal application process. It occurs when a project committer identifies a concrete problem with false positives from a legitimate sender.
- Evolving anti-spam landscape: Many commercial filters that once used the SpamAssassin engine as a base have since moved on to entirely different or heavily customized systems, further reducing the overall relevance of the default SpamAssassin whitelists.
Key considerations
- Prioritize industry best practices: Focus on robust email authentication (SPF, DKIM, DMARC), maintaining clean lists, and sending engaging content to opted-in subscribers. These are the primary drivers of inbox placement. For more, see boost email deliverability rates.
- Engage with specific mailbox providers: If facing deliverability issues, contacting specific mailbox providers or using their postmaster tools (e.g., Google Postmaster Tools) is more effective than trying to influence global SpamAssassin lists. This can help with how to contact ISPs to get off email blacklists.
- Understand custom filtering: Recognize that most sophisticated spam filters, including those using the SpamAssassin framework, heavily customize their rules. Generic SpamAssassin whitelisting is therefore of limited practical benefit.
- Monitor real-time blocklists: It is critical to be aware of your standing on real-time blocklists (RBLs) and DNSBLs, as these have a much more direct and significant impact on deliverability. An in-depth guide to email blocklists provides further context.
Expert view
Expert from Email Geeks suggests that engaging directly with the SpamAssassin project maintainers is the best way to get questions answered about their whitelists and inquire about inclusion. They express skepticism about smaller senders being added, given the caliber of companies already on the list (e.g., eBay, PayPal, Amazon).
Expert view
Expert from Word to the Wise confirms that they are unaware of anyone still actively using SpamAssassin as their primary or core spam filtering engine. They suggest that the technology may have been largely superseded by newer, more advanced solutions in the industry.
What the documentation says
Official SpamAssassin documentation, particularly its rule files, provides direct insight into how its internal whitelists are constructed and managed. It clearly indicates that these lists are hardcoded and not subject to an external application process. The criteria for inclusion revolve around ensuring that legitimate, high-value emails are not incorrectly classified as spam.
Key findings
- Hardcoded rules: SpamAssassin's internal whitelists (like those for SPF and DKIM) are explicitly defined within its source code, as seen in files such as 60_whitelist_spf.cf and 60_whitelist_dkim.cf.
- Lack of proactive application: A committer from the SpamAssassin project explicitly states that there is no process for senders to proactively apply for inclusion in the def_whitelist_auth file.
- Criteria for inclusion: Entries are added when a committer identifies a need to prevent false positives or improve scoring for senders who are known to send only legitimate (ham) emails that users highly value. This is driven by observed problems rather than requests.
- Ad hoc nature of management: Both additions and removals from these internal whitelists are ad hoc and unilateral, without a formal objective policy. The bias of the Project Management Committee (PMC) is towards stability, not agility.
- Local configuration possibilities: System administrators can manually configure SpamAssassin to whitelist specific senders or domains by adding entries to their local configuration files (e.g., local.cf), allowing for custom exceptions.
Key considerations
- Limited influence on core whitelists: Senders should understand that they have virtually no direct control over being added to SpamAssassin's default, hardcoded whitelists. The primary method is for a committer to observe a consistent pattern of legitimate mail from a domain.
- Focus on deliverability fundamentals: Instead of seeking inclusion on these specific lists, senders should prioritize strong email authentication (SPF, DKIM, DMARC), maintaining a clean sender reputation, and adhering to general email best practices. These are far more impactful. Learn more in this advanced guide to email authentication.
- Customization by administrators: Many email server administrators running SpamAssassin will customize its rules and whitelists to fit their specific needs. Therefore, a global hardcoded whitelist entry might not always guarantee delivery if local rules override or add to it. Organizations can refer to resources like how to configure a spam filter in Plesk.
- Engage with users for local whitelisting: The most effective way to ensure emails bypass SpamAssassin filtering for specific recipients is to encourage them to whitelist your address or domain directly in their email client or server. Many hosting providers provide guides, such as HostPapa's guide on Apache SpamAssassin configuration.
Technical article
SpamAssassin's GitHub documentation for 60_whitelist_spf.cf shows that this file contains hardcoded entries for SPF whitelisting. These entries are specific domains believed to be trustworthy, providing a direct mechanism to reduce spam scores for emails originating from them based on SPF authentication.
Technical article
InMotion Hosting's support documentation confirms that SpamAssassin analyzes email messages to evaluate their likelihood of being spam. It logs the results, which can then be used by administrators to filter spam based on predefined thresholds and rules, highlighting the filter's operational mechanism.
Related resources
11 resources
Related pages
How can I convince an email network owner to whitelist my IPs to reduce bounces?
How do I get my emails whitelisted by a recipient's email admin?
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Why Your Emails Are Going to Spam in 2024 and How to Fix It
Boost Email Deliverability Rates: Technical Solutions from Top Performing Senders
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