Summary
The prevailing guidance suggests that while `-all` offers the strongest SPF protection and security when used with DMARC quarantine, it requires careful and meticulous configuration. Experts and email marketers emphasize the importance of thoroughly auditing and authenticating all legitimate sending sources in your SPF record before implementing `-all` to prevent deliverability issues and false positives. A gradual approach, starting with `~all` and actively monitoring SPF reports and DMARC feedback, is widely recommended. Real-world experiences highlight that `-all` can improve email placement but necessitates ongoing maintenance and testing SPF changes is key to making the right change.
Key findings
- Strongest Protection: `-all` provides the strongest level of protection and security for SPF when combined with DMARC.
- Requires Meticulous Configuration: Careful and thorough configuration is essential to prevent unintended blocking of legitimate emails.
- Gradual Approach Recommended: Starting with `~all` and gradually transitioning to `-all` reduces the risk of deliverability issues.
- Monitoring is Crucial: Actively monitoring SPF records, DMARC reports, and DMARC feedback loops is necessary to identify and address potential problems.
- Testing Changes: Testing SPF changes makes you understand the impact of the change.
Key considerations
- Authenticate All Sending Sources: Ensure that all legitimate email sending sources are properly authenticated and included in your SPF record.
- Regular SPF Audits: Conduct regular audits of your SPF records to verify accuracy and identify any unauthorized sending sources.
- Monitor DMARC Feedback: Utilize DMARC reports and feedback loops to identify and address any authentication failures or deliverability issues.
- Gradual Rollout: Implement changes gradually and carefully monitor the impact on email deliverability.
- Organizational Impact: Consider the impact across different business units, as each unit might have its own requirements.
What email marketers say
11 marketer opinions
The consensus is that while `-all` provides stronger security when used with DMARC quarantine by strictly enforcing SPF, it's crucial to ensure all legitimate email sources are authenticated in your SPF record to avoid deliverability issues. A gradual approach, starting with `~all` and thorough monitoring, is recommended before transitioning to `-all`. Real-world experiences show that `-all` can improve email placement but requires careful maintenance. Testing SPF changes is also essential to understand the impact.
Key opinions
- Security vs. Deliverability: `-all` offers better security due to strict SPF enforcement, but incorrect setup can severely impact deliverability.
- Gradual Implementation: A staged approach, starting with `~all` and then moving to `-all`, minimizes the risk of blocking legitimate emails.
- Monitoring is Crucial: Regularly monitoring SPF records and DMARC reports is essential to identify and resolve deliverability issues.
- Testing Changes: Testing SPF changes makes you understand the impact of the change.
Key considerations
- Authentication of All Sources: Verify that all legitimate email sending sources are properly authenticated in your SPF record.
- DMARC Reporting: Utilize DMARC reports to identify and address any authentication failures.
- Business Unit Awareness: Take into consideration other business units using email within the organisation before changing to `-all`.
Marketer view
Email marketer from Email Marketing Tips suggests using `-all` only when you are absolutely sure that all of your email sending services are correctly configured in your SPF record. Incorrect configuration can lead to significantly lower email deliverability.
27 Oct 2022 - Email Marketing Tips
Marketer view
Email marketer from Reddit mentions that while `-all` is stricter, it's crucial to ensure that all legitimate sending sources are included in your SPF record to avoid deliverability issues. He suggests monitoring SPF results carefully after implementing `-all`.
23 Feb 2022 - Reddit
What the experts say
1 expert opinions
An expert advises that while `-all` provides the strongest SPF protection, meticulous configuration is essential. Thoroughly auditing sending sources and monitoring SPF reports with DMARC feedback are crucial to avoid blocking legitimate emails.
Key opinions
- Strongest Protection: `-all` offers the strongest protection for SPF.
- Meticulous Configuration Needed: Careful setup is required to prevent unintended blocking of legitimate email.
Key considerations
- Auditing Sources: Thoroughly audit all sending sources to ensure they are authorized.
- Monitoring: Monitor SPF reports and DMARC feedback to identify and address issues.
Expert view
Expert from Word to the Wise advises that while `-all` offers the strongest SPF protection, it requires meticulous configuration. She recommends thoroughly auditing sending sources to avoid blocking legitimate emails. She also suggests monitoring SPF reports and using DMARC feedback to ensure all systems are working correctly.
8 Feb 2024 - Word to the Wise
What the documentation says
5 technical articles
Documentation consistently indicates that using `-all` creates a hard fail, instructing recipient mail servers to reject messages failing the SPF check. While offering the strongest authentication and protection against spoofing when paired with DMARC, it requires an accurate SPF record and thorough testing/monitoring to prevent legitimate emails from being rejected.
Key findings
- Hard Fail: `-all` implements a hard fail, causing rejection of emails failing SPF.
- Strongest Authentication: `-all` offers the strongest authentication when combined with DMARC.
- Better Security: `-all` is generally recommended for improved security when using DMARC.
Key considerations
- Accuracy of SPF Record: Ensure the SPF record is completely accurate to avoid blocking legitimate emails.
- Testing and Monitoring: Rigorous testing and continuous monitoring are essential to prevent unintended consequences.
Technical article
Documentation from AuthSMTP highlights the importance of a well-defined SPF record in tandem with DMARC. When using a `p=quarantine` or `p=reject` DMARC policy, they recommend `-all` for the strongest authentication.
17 Jul 2021 - AuthSMTP
Technical article
Documentation from DMARC.org explains that using `-all` creates a 'hard fail', instructing recipient mail servers to reject messages that fail the SPF check. They recommend this for maximum protection against spoofing once SPF is properly configured.
13 Dec 2023 - DMARC.org
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