Summary
SpamAssassin significantly affects email deliverability through its rule-based scoring system, where emails exceeding a defined threshold are flagged as spam. Factors influencing SpamAssassin scores include poor HTML coding, spam trigger words, broken links, lack of authentication (SPF, DKIM, DMARC), and sender reputation. Blacklisting severely impacts deliverability, as SpamAssassin consults blacklists. Proper email authentication, maintaining a positive sender reputation, and ensuring list hygiene are crucial for evading SpamAssassin filters. While triggering custom SpamAssassin rules might not lead to immediate blocking, it's wise to periodically review email practices. Testing emails with tools like GlockApps before sending them to a large audience, using dedicated IPs, avoiding URL shorteners and excessive capitalization, and carefully choosing TLDs can further improve deliverability.
Key findings
- Scoring Mechanism: SpamAssassin employs a rule-based scoring system; exceeding a threshold results in spam classification.
- Triggering Rules: Triggering custom SpamAssassin rules doesn't guarantee immediate blocking but signals a need for review.
- Email Attributes: Poor HTML, spam words, broken links, and lacking authentication negatively impact SpamAssassin scores.
- Sender Reputation: Sender reputation is crucial; SpamAssassin heavily relies on it to assess trustworthiness.
- Authentication Standards: Implementing SPF, DKIM, and DMARC is essential for bypassing spam filters and ensuring legitimate email delivery.
- Blacklisting Impact: Being blacklisted significantly damages deliverability, as SpamAssassin consults blacklists.
- List Hygiene Importance: Maintaining a clean email list reduces bounce rates and enhances sender reputation.
- TLD Selection: Using reputable TLDs can help reduce the chances of being flagged as spam.
Key considerations
- Rule Review: Periodically review and address factors that trigger SpamAssassin rules.
- HTML & Content Optimization: Ensure your HTML code is clean and avoid spam trigger words in email content.
- Authentication Implementation: Implement and maintain proper email authentication protocols (SPF, DKIM, DMARC).
- Reputation Monitoring: Monitor sender reputation to identify and address potential issues promptly.
- URL and Formatting: Avoid using URL shorteners and excessive capitalization or exclamation points.
- Pre-send Testing: Test your emails with tools like GlockApps to assess potential deliverability issues before widespread sending.
- Blacklist Monitoring: Regularly check if your domain or IP is blacklisted using tools like MXToolbox.
- IP Reputation Management: Consider using a dedicated IP to manage your sender reputation effectively.
- List Management Practices: Regularly clean your email list to remove inactive subscribers and address bounces.
- Holistic view: Take a holistic view of deliverability as mainstream mail providers are taking more and more of a broader overview of your emails to determine spam.
What email marketers say
12 marketer opinions
SpamAssassin rules significantly impact email deliverability by evaluating various email attributes. Triggering these rules can lead to emails being flagged as spam, hindering their arrival in recipients' inboxes. To improve deliverability, it's crucial to avoid spam trigger words, ensure proper email authentication (SPF, DKIM, DMARC), maintain a good sender reputation, use clean and well-structured HTML code, avoid URL shorteners, test emails before sending, use dedicated IPs, maintain good list hygiene, and avoid excessive use of all caps and exclamation points. Understanding and adhering to these best practices helps bypass SpamAssassin's filters and enhances the likelihood of successful email delivery.
Key opinions
- Custom Rules: Triggering custom SpamAssassin rules may not result in immediate blocking but is a good idea to check from time to time.
- Spamhaus TLDs: Check the Spamhaus list of abused TLDs to assess their potential impact on deliverability.
- Content Triggers: Using spam trigger words negatively impacts deliverability; focus on clear, concise content.
- Authentication: Proper email authentication (SPF, DKIM, DMARC) is crucial for avoiding spam filters.
- URL Shorteners: Using URL shorteners can trigger spam filters; use full, transparent URLs.
- HTML Coding: Poorly coded HTML emails can trigger spam filters; use clean, well-structured HTML.
- Sender Reputation: Maintaining a good sender reputation is key to bypassing spam filters.
- Email Testing: Before sending, test emails with tools like GlockApps to identify deliverability issues.
- Dedicated IPs: Using a dedicated IP address can improve sender reputation.
- List Hygiene: Good list hygiene is critical for improving email deliverability.
Key considerations
- TLD Choice: Carefully consider the TLD used for your domain, as some are more prone to abuse.
- Content Optimization: Regularly review email content to avoid spam trigger words and ensure clarity.
- Authentication Setup: Implement and maintain proper email authentication protocols (SPF, DKIM, DMARC).
- Reputation Monitoring: Monitor your sender reputation to identify and address any issues promptly.
- Code Quality: Ensure your HTML code is clean and well-structured to avoid triggering spam filters.
- Avoid shortcuts: Avoid URL shorteners and excessive capitalization/exclamation points to maintain trust.
- Email Tests: Regularly test your emails before sending them to catch potential problems.
- IP reputation: Consider using a dedicated IP address to manage sender reputation effectively.
- Clean lists: Prioritize maintaining a clean and engaged email list to improve deliverability.
- Holistic approach: Take a holistic view of deliverability as mainstream mail providers are taking more and more of a broader overview of your emails to determine spam.
Marketer view
Email marketer from HubSpot recommends testing emails with tools like GlockApps before sending them to a large audience. These tools simulate different spam filters, including SpamAssassin, and provide insights into potential deliverability issues. Testing helps identify and fix problems before they impact the email campaign.
30 Sep 2024 - HubSpot
Marketer view
Email marketer from GlockApps shares that using a dedicated IP address can improve sender reputation and email deliverability. With a dedicated IP, the sender is not sharing the IP with other senders who might engage in spammy practices. A good IP reputation helps bypass spam filters like SpamAssassin.
22 Aug 2021 - GlockApps
What the experts say
3 expert opinions
SpamAssassin rules impact email deliverability by evaluating email attributes and assigning scores. Low-scoring rules like KAM_NUMSUBJECT might indicate potentially problematic subject line formats. Factors such as poor HTML coding, spam trigger words, broken links, and missing authentication records can increase SpamAssassin scores, reducing inbox placement. A crucial element is maintaining a positive sender reputation through consistent, valuable content, minimizing bounces, and using feedback loops. Regularly reviewing email practices based on SpamAssassin insights helps ensure better deliverability.
Key opinions
- Rule Scores: SpamAssassin uses a rule-based scoring system; exceeding a threshold flags emails as spam.
- Subject Line Formats: Dodgy subject line formats (e.g., 'Your Invoice #12345') can trigger spam rules.
- Email Attributes: Poor HTML, spam words, broken links and missing authentication negatively impact scores.
- Sender Reputation: Sender reputation significantly influences deliverability.
Key considerations
- Review Subject Lines: Reconsider subject line formats that might be flagged as suspicious.
- Optimize Email Attributes: Address issues like poor HTML, spam words, broken links, and missing authentication.
- Improve Reputation: Improve sender reputation by sending consistent, valuable content and minimizing bounces.
- Regular Review: Take a second look at email practices based on SpamAssassin insights and reports.
Expert view
Expert from Word to the Wise emphasizes the impact of sender reputation on email deliverability. They note that SpamAssassin and other filters use sender reputation as a key factor in determining whether to deliver an email. Improving sender reputation requires consistent email practices, such as sending relevant content, avoiding high bounce rates, and implementing feedback loops.
19 Aug 2023 - Word to the Wise
Expert view
Expert from Spamresource explains that SpamAssassin evaluates various email attributes to determine its score. Factors like poor HTML coding, use of spam trigger words, broken links, and lack of proper authentication records (SPF, DKIM) can increase the SpamAssassin score, negatively impacting deliverability. Addressing these factors is crucial to improve inbox placement.
24 Aug 2024 - Spamresource
What the documentation says
5 technical articles
SpamAssassin's rule-based scoring system significantly affects email deliverability; emails exceeding a defined score threshold are marked as spam. Spam filters, like SpamAssassin, consult blacklists, making blacklist status a critical factor. Sender reputation is crucial for trustworthiness. DKIM and SPF are vital for email authentication, preventing forgery and improving deliverability. Maintaining good reputation and utilizing authentication methods are essential for evading SpamAssassin's filters.
Key findings
- Scoring System: SpamAssassin employs a rule-based scoring system; exceeding the threshold results in spam classification.
- Blacklist Impact: Blacklisting severely damages deliverability, as SpamAssassin consults blacklists.
- Reputation Importance: Sender reputation is a key factor; SpamAssassin uses reputation data to assess sender trustworthiness.
- Authentication Benefits: DKIM and SPF improve deliverability through enhanced email authentication and sender verification.
Key considerations
- Monitor Scores: Regularly monitor SpamAssassin scores and address issues that contribute to higher scores.
- Check Blacklists: Check blacklist status using tools like MXToolbox to ensure you aren't listed.
- Reputation Management: Focus on building and maintaining a positive sender reputation.
- Implement Authentication: Implement and maintain SPF and DKIM records to authenticate emails and improve deliverability.
Technical article
Documentation from DKIM.org states that DKIM (DomainKeys Identified Mail) helps improve email deliverability by providing a digital signature that verifies the sender's identity. This makes it more difficult for spammers to forge emails and improves sender reputation, reducing the likelihood of emails being flagged by spam filters.
7 Apr 2022 - DKIM.org
Technical article
Documentation from MXToolbox explains that being blacklisted can severely impact email deliverability. SpamAssassin and other spam filters often consult blacklists to identify spam sources. MXToolbox provides tools to check if a domain or IP address is on any major blacklists.
24 Oct 2022 - MXToolbox
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