Summary
SPF alignment, as reported by services like Validity, often shows 0% even when SPF passes because the domain used for SPF authentication (the 'MAIL FROM' or envelope sender) doesn't match the domain in the 'From' header. This is a common scenario when using third-party sending services or ESPs (like Mailchimp, Constant Contact, Sendgrid, and Amazon SES) that utilize their own infrastructure and domains for sending on behalf of customers. While SPF can pass based on the ESP's domain, DMARC requires alignment between the authenticated domain and the 'From' header domain to ensure the email truly originates from the claimed sender. DMARC can pass with either SPF or DKIM alignment. If DKIM is used, the DKIM domain also needs to align for DMARC to pass. Solutions involve configuring custom MAIL FROM settings, using a custom return-path, or implementing DKIM to achieve proper alignment.
Key findings
- Domain Mismatch: The 'MAIL FROM' domain (used for SPF) doesn't match the 'From' header domain.
- Third-Party Senders: ESPs and third-party services commonly use their own domains for the 'MAIL FROM' address.
- DMARC Requirement: DMARC requires SPF alignment (or DKIM alignment) for proper authentication and deliverability.
- Passing vs. Aligning: SPF can pass based on the sending server's domain without aligning with the sender's domain in the 'From' header.
- DKIM as Alternative: DKIM can be used for DMARC compliance if it passes and aligns, even if SPF fails alignment.
Key considerations
- Check Domains: Verify the 'MAIL FROM' and 'From' domains and ensure they are configured correctly.
- Custom Configuration: Configure custom MAIL FROM settings or a custom return-path domain with your ESP to align with your sending domain.
- Implement DKIM: Implement DKIM signing using your own domain to achieve alignment, especially if SPF alignment is difficult.
- Understand DMARC: Grasp how DMARC uses SPF and DKIM alignment to determine email authenticity and improve deliverability.
- ESP-Specifics: Investigate how specific ESPs handle SPF, DKIM, and DMARC alignment, and adjust settings accordingly.
- Alignment Type: Understand if your DMARC policy is using strict or relaxed alignment. Strict alignment requires an exact domain match while relaxed alignment allows for subdomains.
What email marketers say
9 marketer opinions
SPF alignment failures, despite SPF passing, primarily occur because the domain used for SPF authentication (MAIL FROM or return-path) does not match the domain in the 'From' header. This discrepancy is common when using third-party sending services or ESPs, which often use their own infrastructure and domains for sending emails on behalf of their customers. Although SPF can pass based on the ESP's domain, it doesn't align with the sender's domain, impacting DMARC compliance. Solutions involve configuring custom MAIL FROM settings, using a custom return-path domain, or implementing DKIM.
Key opinions
- Domain Mismatch: The 'MAIL FROM' domain (used for SPF) differs from the 'From' header domain.
- Third-Party Senders: ESPs and third-party services often use their own domains for 'MAIL FROM'.
- DMARC Requirement: DMARC requires SPF alignment for proper authentication.
- Passing vs. Aligning: SPF can pass based on the sending server's domain without aligning with the sender's domain.
- Shared Infrastructure: Using shared sending infrastructure can cause alignment issues due to different 'MAIL FROM' domains.
Key considerations
- Check Domains: Verify the 'MAIL FROM' and 'From' domains to ensure they match or are appropriately related.
- Custom Configuration: Configure custom 'MAIL FROM' settings or a custom return-path domain with your ESP.
- Implement DKIM: Consider implementing DKIM for domain authentication as an alternative or complementary method.
- DMARC Impact: Understand that SPF alignment issues can negatively impact DMARC compliance and email deliverability.
- ESP Defaults: Be aware that ESP default settings might not provide SPF alignment and require manual configuration.
Marketer view
Email marketer from GlockApps responds that SPF alignment issues can occur because the return-path domain is different from the from domain. They suggest checking the 'return-path' and 'from' domains to ensure they match, or configure a custom return-path domain to align with the 'from' domain.
13 Dec 2024 - GlockApps
Marketer view
Email marketer from Sendgrid suggests that the most common reason for SPF passing but failing to align is the use of a shared sending infrastructure where the MAIL FROM domain is different from the From domain. They suggest using a custom MAIL FROM domain or DKIM as potential solutions.
20 Feb 2025 - Sendgrid
What the experts say
6 expert opinions
SPF alignment failures, even when SPF passes, stem from the domain used for SPF authentication (MAIL FROM) not matching the domain in the 'From' header. This is common with ESPs like Mailchimp, Constant Contact, Sendgrid, and Amazon SES, unless configured otherwise. SPF authenticates the sending server, but DMARC requires the domains to align. DMARC can pass with either aligned SPF or aligned DKIM. If DKIM passes but the DKIM domain doesn't align, DMARC will fail. The ultimate goal of alignment is to ensure that the authorized sending domain matches the domain displayed to the recipient.
Key opinions
- Domain Mismatch: The 'MAIL FROM' domain (SPF) doesn't match the 'From' header domain.
- ESP Defaults: Many ESPs, by default, cause SPF to pass without alignment.
- DMARC Requirement: DMARC requires either SPF or DKIM to pass *and* align.
- SPF vs. DMARC: SPF only authenticates the sending server, while DMARC authenticates the domain presented to the recipient.
- DKIM's Role: DKIM can be used for DMARC compliance if it passes and aligns, even if SPF fails alignment.
Key considerations
- Check Configuration: Verify 'MAIL FROM' and 'From' domains and configure ESPs for alignment.
- DMARC Requirements: Understand DMARC's need for either SPF or DKIM alignment.
- DKIM Setup: Ensure DKIM is properly configured and aligned if relying on it for DMARC compliance.
- ESP-Specifics: Investigate how specific ESPs handle SPF and DKIM alignment.
- Overall Strategy: Develop a holistic email authentication strategy encompassing SPF, DKIM, and DMARC.
Expert view
Expert from Spam Resource explains that SPF authenticates the server sending the email but doesn't necessarily align with the domain in the 'From' header, which DMARC requires. The domains in the 'MAIL FROM' and 'From' header must match or be related for proper alignment.
10 Jun 2022 - Spam Resource
Expert view
Expert from Email Geeks clarifies that SPF needs to pass and be aligned for DMARC to pass, but DMARC can also pass if DKIM passes and is aligned independently of SPF. DMARC only needs one (SPF or DKIM) to pass and align in order to pass.
20 May 2024 - Email Geeks
What the documentation says
5 technical articles
SPF alignment fails when the domain in the 'MAIL FROM' (envelope sender or return-path) address doesn't match the domain in the 'From' header. This mismatch prevents DMARC from properly authenticating email using SPF, even if SPF passes based on the 'MAIL FROM' domain. Third-party email services often cause this issue by using their own 'MAIL FROM' domains. Alignment requires an exact match or subdomain relationship between the domains, depending on DMARC's alignment mode.
Key findings
- Domain Mismatch: 'MAIL FROM' domain differs from 'From' header domain.
- DMARC Requirement: SPF alignment is necessary for DMARC authentication with SPF.
- Third-Party Impact: Third-party services often cause alignment failures due to their 'MAIL FROM' domains.
- Alignment Modes: DMARC supports strict or relaxed alignment, requiring an exact match or subdomain relationship.
Key considerations
- Check Domains: Verify the 'MAIL FROM' and 'From' domains for consistency.
- Configure Alignment: Ensure domains align based on DMARC alignment mode (strict or relaxed).
- Understand DMARC: Comprehend DMARC's reliance on alignment for effective authentication.
- Third-Party Settings: Review configurations of third-party email services to achieve proper SPF alignment.
Technical article
Documentation from AuthSMTP explains that the domain in the MAIL FROM and From header must match to satisfy SPF Alignment. This means that if your SPF record is configured correctly and SPF passes but your SPF alignment is still 0%, the domain in your From and MAIL FROM headers do not match, causing SPF alignment to fail.
20 Oct 2022 - AuthSMTP
Technical article
Documentation from DMARC.org explains that for SPF to align, the domain in the 'MAIL FROM' (also known as the envelope from or return-path) must exactly match the organizational domain in the 'From' header, or be a subdomain of it, depending on whether 'strict' or 'relaxed' alignment is used. If there's no match, SPF will pass but not align.
3 May 2023 - DMARC.org
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