Is DMARC reject policy mandatory for From and Return-Path alignment?

Summary

The general consensus from email marketers, experts, and DMARC documentation is that a 'reject' policy in DMARC does **not** require the 'From' and 'Return-Path' headers to be strictly aligned. Instead, the critical requirement is that either SPF or DKIM authentication methods align with the domain presented in the 'From' header. This alignment validates the sender's authorization to use the 'From' domain, even if the underlying infrastructure uses a different domain for the 'Return-Path'. Emails that fail to meet the SPF or DKIM alignment criteria, will be rejected by recipient mail servers when the 'reject' policy is enforced.

Key findings

  • No Strict 'From'/'Return-Path' Alignment Required: DMARC's 'reject' policy doesn't mandate that the 'From' and 'Return-Path' domains must be identical.
  • SPF or DKIM Alignment is Crucial: Passing DMARC depends on the successful alignment of either SPF or DKIM authentication with the domain found in the 'From' header.
  • 'Reject' Policy Enforces Authentication: With a 'reject' policy, emails failing the DMARC authentication check (SPF or DKIM alignment failure) should be rejected by the recipient's mail server.

Key considerations

  • Proper SPF/DKIM Configuration: Ensure that either SPF or DKIM is correctly configured and aligns with your 'From' domain to comply with DMARC.
  • DMARC Policy Implementation: Understanding the impact of the 'reject' policy is essential for managing email deliverability and sender reputation.
  • DMARC Monitoring and Reporting: Utilize DMARC reporting to monitor authentication results and identify any configuration or alignment issues that could affect email delivery.

What email marketers say
8Marketer opinions

The consensus among email marketers and experts is that a DMARC 'reject' policy does not mandate a strict alignment between the 'From' and 'Return-Path' headers. Instead, it requires that either SPF or DKIM authentication mechanisms align with the domain presented in the 'From' header. This ensures that emails failing DMARC checks due to authentication failures are rejected, while still allowing legitimate emails to pass even if the 'From' and 'Return-Path' domains differ, provided they are properly authenticated.

Key opinions

  • Alignment Focus: DMARC 'reject' primarily focuses on the alignment of authentication methods (SPF or DKIM) with the 'From' domain, rather than direct alignment between 'From' and 'Return-Path'.
  • Authentication Prerequisite: For an email to pass DMARC with a 'reject' policy, either SPF or DKIM must authenticate and align with the 'From' domain.
  • Rejection on Failure: Emails failing both SPF and DKIM alignment checks are intended to be rejected by receiving mail servers when the DMARC policy is set to 'reject'.

Key considerations

  • Authentication Method: Ensure that either SPF or DKIM is properly configured and aligned with the 'From' domain to pass DMARC, regardless of the 'Return-Path'.
  • DMARC Policy Impact: Understand that the 'reject' policy tells receiving servers to reject unauthenticated emails, improving domain security and deliverability.
  • Monitoring and Reporting: Implement DMARC reporting to monitor authentication results and identify any issues with SPF or DKIM alignment.
Marketer view

Email marketer from Mailhardener Blog explains that when DMARC policy is set to reject, it means that emails failing DMARC checks should be rejected by the recipient's mail server. However, this doesn't inherently mandate that 'From' and 'Return-Path' must be aligned, but it's crucial that either SPF or DKIM aligns for DMARC to pass.

October 2022 - Mailhardener Blog
Marketer view

Email marketer from Reddit explains that the reject policy in DMARC tells receiving mail servers to reject messages that fail DMARC checks. While alignment between the 'From' header and 'Return-Path' isn't explicitly enforced, it's implied because either SPF or DKIM needs to pass and align with the 'From' domain for a message to be considered legitimate.

April 2022 - Reddit
Marketer view

Email marketer from SparkPost states that DMARC requires alignment between the domain in the 'From' address and the domain used for SPF or DKIM authentication. A 'reject' policy means that messages failing this alignment (and therefore failing DMARC) should be rejected, but the alignment is focused on the authentication mechanisms, not necessarily a direct comparison between 'From' and 'Return-Path'.

May 2022 - SparkPost
Marketer view

Email marketer from EasyDMARC answers that a DMARC policy of 'reject' means that non-aligned emails will be rejected if they fail authentication. However, it does not mean From and Return-Path need to be strictly aligned as long as DKIM alignment passes.

August 2023 - EasyDMARC
Marketer view

Email marketer from AuthSMTP shares that a DMARC record with a policy set to reject means that if the email fails the DMARC authentication checks it should be rejected. For an email to pass DMARC one of SPF or DKIM must pass and be aligned.

January 2023 - AuthSMTP
Marketer view

Email marketer from GlockApps Blog shares that when DMARC is set to 'reject', emails that fail both SPF and DKIM alignment checks are supposed to be rejected by the receiving mail server. Alignment of the 'From' and 'Return-Path' isn't directly enforced, the underlying authentication mechanisms must align with the 'From' domain for DMARC to validate the email.

January 2022 - GlockApps Blog
Marketer view

Email marketer from Postmark states the `reject` policy tells receiving servers what to do with messages that fail the DMARC check. DMARC relies on SPF and DKIM passing authentication and alignment checks. From and Return-Path alignment is not required as long as DKIM alignment passes.

March 2024 - Postmark
Marketer view

Marketer from Email Geeks explains that DMARC alignment isn't necessary if DKIM aligns and authenticates.

August 2024 - Email Geeks

What the experts say
3Expert opinions

Experts agree that a DMARC 'reject' policy doesn't necessitate a direct match between the 'From' and 'Return-Path' headers. The core requirement is that either SPF or DKIM authentication aligns with the 'From' domain. This alignment verifies that the sender is authorized to use the 'From' domain, even if the 'Return-Path' differs, as long as the authentication passes.

Key opinions

  • Authentication Alignment is Key: DMARC relies on SPF or DKIM alignment with the 'From' domain for validation.
  • Flexible Header Requirements: Strict matching of 'From' and 'Return-Path' is not a mandatory condition for passing DMARC.
  • Authorization Verification: Alignment of SPF or DKIM with the 'From' domain serves to verify the sender's authorization.

Key considerations

  • Ensure SPF/DKIM Alignment: Properly configure SPF or DKIM so that one of these methods aligns with your 'From' domain.
  • Understand DMARC Rejection Impact: Emails that fail both SPF and DKIM alignment will be rejected by receiving servers under a 'reject' policy.
  • Monitor DMARC Reports: Regularly review DMARC reports to ensure proper authentication and alignment and to identify any potential issues.
Expert view

Expert from Email Geeks explains that either SPF or DKIM must align (and pass) for DMARC to pass.

October 2023 - Email Geeks
Expert view

Expert from Spam Resource explains that DMARC policies (including 'reject') do not require that the 'From' and 'Return-Path' domains match exactly. The key requirement is that the email passes either SPF or DKIM authentication and that the authenticating domain aligns with the domain presented in the 'From' address. This ensures that the sender is authorized to use the 'From' domain, even if the underlying infrastructure uses a different domain for the 'Return-Path'.

June 2022 - Spam Resource
Expert view

Expert from Word to the Wise explains that the DMARC 'reject' policy does not mandate that the 'From' and 'Return-Path' headers be strictly aligned. Instead, it requires that either the SPF or DKIM authentication mechanisms align with the domain in the 'From' header. This means that as long as one of these authentication methods validates and aligns, the email can pass DMARC even if the 'From' and 'Return-Path' are not identical.

June 2023 - Word to the Wise

What the documentation says
5Technical articles

DMARC documentation from various sources consistently indicates that while a 'reject' policy increases the stringency of DMARC enforcement, it doesn't mandate a direct match between the 'From' and 'Return-Path' domains. Instead, DMARC relies on the alignment of either SPF or DKIM with the 'From' domain. For DMARC to pass, at least one of these authentication methods must successfully validate and align with the 'From' domain, allowing flexibility in the 'Return-Path' as long as authentication is solid.

Key findings

  • Authentication Alignment: DMARC's primary requirement is the alignment of either SPF or DKIM with the 'From' domain, rather than strict 'From' and 'Return-Path' alignment.
  • Flexible 'Return-Path': The 'Return-Path' domain doesn't necessarily need to match the 'From' domain, as long as SPF or DKIM authenticates and aligns.
  • DMARC Policy Impact: The 'reject' policy dictates how receiving mail servers should handle messages that fail DMARC validation, typically by rejecting them.

Key considerations

  • Proper Authentication Setup: Ensure that either SPF or DKIM is correctly configured and aligned with the 'From' domain to achieve DMARC compliance.
  • DMARC Monitoring: Regularly monitor DMARC reports to verify proper alignment and authentication, and to identify and address any potential issues.
  • SPF for DMARC: When using SPF for DMARC validation, ensure that the 'From' domain aligns with the domain used to authenticate with SPF (the domain in the 'Return-Path').
Technical article

Documentation from Valimail explain that one of the requirements for DMARC is to meet either SPF or DKIM alignment. The From and Return-Path do not need to be aligned, only one of the authentication methods.

March 2022 - Valimail
Technical article

Documentation from DMARC.org details that for DMARC to pass based on SPF, the 'From' domain and the domain used to authenticate with SPF (i.e., the domain in the 'Return-Path') must align. Alignment can be strict or relaxed depending on the configuration but is necessary for SPF to be a valid authenticator under DMARC.

June 2021 - DMARC.org
Technical article

Documentation from Microsoft details how DMARC works with Exchange Online and explains that for a message to pass DMARC, it must either pass SPF authentication and SPF alignment, or DKIM authentication and DKIM alignment. The From and Return-Path do not need to be aligned, only one of the authentication methods.

March 2023 - Microsoft
Technical article

Documentation from Google explains that Gmail uses DMARC to verify incoming mail. If a message fails DMARC validation, what happens next depends on the sender's DMARC policy. For an email to pass, either SPF or DKIM must pass and be aligned.

September 2023 - Google Workspace Admin Help
Technical article

Documentation from RFC 7489, the standard defining DMARC, explains that DMARC relies on the alignment of domains between the 'From' header and the authentication results (SPF or DKIM). While a 'reject' policy doesn't intrinsically demand strict alignment of 'From' and 'Return-Path', it necessitates that the authentication method used (SPF or DKIM) does align with the 'From' domain.

July 2022 - RFC Editor