Summary
DMARC passing depends on two primary conditions: an email must successfully authenticate through either SPF or DKIM, and the domain in the user-visible 'From' header must align with the domain used for that authentication. Identifier alignment is the critical verification process that ensures the displayed sender is genuinely associated with the authenticated domain, thereby bolstering anti-spoofing efforts.
Key findings
- DMARC Pass Definition: DMARC passes when an email successfully authenticates via either SPF or DKIM, and the domain that passed this authentication aligns with the domain in the visible 'From' header.
- Identifier Alignment Explained: Identifier alignment is the process where the domain presented to the user in the 'From' header (RFC5322.From) matches the domain used for SPF authentication (RFC5321.MailFrom/Return-Path) or DKIM authentication (the 'd=' tag in the signature).
- Purpose of Alignment: This alignment check is crucial for DMARC's anti-spoofing capabilities, as it ensures the displayed sender is legitimately authorized by the domain that sent the email.
- Alignment Strictness: Alignment can be configured as 'strict,' requiring an exact domain match, or 'relaxed,' which allows subdomains to match the organizational domain, offering flexibility in how closely domains must correspond.
Key considerations
- Alignment's Criticality: DMARC validation requires identifier alignment; even if SPF or DKIM individually pass, DMARC will fail if the 'From' header domain does not align with the authenticated domain.
- User Trust and Anti-Phishing: Identifier alignment directly connects the visible 'From' domain to the authenticated domain, fostering trust and actively preventing phishing attempts that use legitimate-looking senders.
- Explaining to Others: When explaining identifier alignment, it can be helpful to visualize the concept, such as pointing out in reporting data that the SPF or DKIM domain must match the 'From' domain, or simply stating that the domains need to be 'obviously the same'.
- Tailored Explanations: For complex topics like DMARC, it's often best to start with a straightforward explanation and only delve into more technical details if the audience demonstrates a need or desire for deeper understanding.
What email marketers say
11 marketer opinions
DMARC ensures email authenticity by requiring that an email not only passes either SPF or DKIM validation, but also that the sender's visible 'From' domain precisely matches, or 'aligns' with, the domain that passed these security checks. This crucial 'identifier alignment' step is fundamental to preventing email spoofing and phishing attacks.
Key opinions
- DMARC Pass Condition: DMARC passes when an email successfully authenticates via either SPF or DKIM, and crucially, the domain visible in the 'From' header aligns with the domain used for that authentication.
- Defining Identifier Alignment: Identifier alignment is the specific verification process where the domain found in the RFC5322.From header (the user-visible sender) matches the RFC5321.MailFrom domain for SPF, or the 'd=' tag domain within the DKIM signature.
- Purpose of Alignment: This alignment check is paramount for DMARC's anti-spoofing capabilities, as it guarantees that the displayed sender is legitimately authorized by the domain that sent the email, preventing unauthorized domain use.
- Alignment Strictness Levels: Identifier alignment can be configured with a 'strict' mode, which demands an exact domain match, or a 'relaxed' mode, which permits subdomains to align with the organizational domain, offering flexibility in how closely domains correspond.
Key considerations
- Alignment is Essential: For DMARC to validate successfully, identifier alignment is a non-negotiable requirement; merely passing SPF or DKIM individually is insufficient if the 'From' header domain does not properly align with the authenticated domain.
- Anti-Spoofing and Trust: Identifier alignment stands as DMARC's foundational defense against spoofing, directly connecting the user-visible sender domain to a verifiable, authenticated domain, which significantly builds recipient trust and thwarts phishing attempts.
- Simplifying Explanations: When clarifying DMARC passing and identifier alignment, it is often most effective to begin with a straightforward explanation- for instance, by stating that the domains need to be 'obviously the same'- and then delve into more technical specifics only if the audience requires deeper understanding.
- Practical Explanation Methods: A tangible way to illustrate identifier alignment involves reviewing DMARC reporting data with recipients and highlighting how one of the SPF or DKIM domain columns must match the 'From' domain, making the concept more concrete.
Marketer view
Email marketer from Email Geeks explains that DKIM and SPF are methods for a sender to take responsibility for an email, and DMARC allows a domain owner to take responsibility for all mail they send via DKIM or SPF. They further clarify that "identifier alignment" is essentially a technical term for domains being "obviously the same".
2 Dec 2022 - Email Geeks
Marketer view
Email marketer from Email Geeks shares advice on explaining complex topics like DMARC, suggesting to keep the explanation simple initially and elaborate only if the audience has further questions, as not everyone needs or will understand the intricate details.
25 May 2022 - Email Geeks
What the experts say
3 expert opinions
For an email to achieve DMARC passing, it's essential that either SPF or DKIM authentication succeeds, and critically, the domain in the visible 'From' header aligns with the domain authenticated by SPF or DKIM. This 'identifier alignment' serves as the cornerstone of DMARC's effectiveness, ensuring the legitimacy of the sender's domain and providing a concise explanation for its function.
Key opinions
- DMARC Pass Logic: DMARC passes only when an email successfully authenticates via SPF or DKIM, and the domain that passed authentication matches the domain found in the email's visible 'From' header.
- Alignment Definition: Identifier alignment means the domain presented in the RFC5322.From header precisely corresponds to the RFC5321.MailFrom domain for SPF or the 'd=' domain in the DKIM signature.
- Alignment Purpose: This critical alignment check is DMARC's mechanism to prevent email spoofing, verifying that the sender shown to recipients is genuinely authorized by the domain that sent the email.
Key considerations
- Alignment Is Key: For DMARC to pass, identifier alignment is mandatory; even if SPF or DKIM individually authenticate, DMARC will fail if the 'From' header domain does not align with the authenticated domain.
- Fighting Spoofing: Identifier alignment strengthens email security by linking the user-visible 'From' domain to a verified, authenticated domain, which is crucial for preventing spoofing and building recipient trust.
- Simple Explanation: To concisely describe DMARC passing, explain that an email needs either SPF or DKIM to pass, and the domain shown in the 'From' header must match the domain that passed that authentication.
Expert view
Expert from Email Geeks explains that for DMARC to pass, either SPF or DKIM must pass, and the domain that passes must be the same as the domain in your visible From header.
13 Apr 2023 - Email Geeks
Expert view
Expert from Spam Resource explains that for DMARC to pass, a message must successfully authenticate with either SPF or DKIM, and crucially, the domain in the visible 'From' header (RFC5322.From) must align with the domain used for SPF authentication (RFC5321.MailFrom) or DKIM authentication (the d= domain in the signature). Without this identifier alignment, DMARC will fail, even if SPF or DKIM individually passed.
15 Sep 2023 - Spam Resource
What the documentation says
5 technical articles
The DMARC standard ensures email authenticity by requiring that an email successfully passes either SPF or DKIM authentication, and crucially, that the domain in the visible 'From' header aligns with the domain used for that authentication. This vital 'identifier alignment' process guarantees that the sender seen by the recipient is legitimately connected to the authenticated domain, bolstering trust and combating spoofing.
Key findings
- Dual Requirement: For DMARC to pass, an email must fulfill two criteria: successful authentication by either SPF or DKIM, and alignment between the 'From' header domain and the authenticated domain.
- Domain Matching: Identifier alignment specifically dictates that the domain in the RFC5322.From header must match the RFC5321.MailFrom domain for SPF, or the 'd=' tag domain for DKIM.
- Core Security Function: This alignment verification is DMARC's primary defense against email spoofing and phishing, ensuring the visible sender is genuinely authorized.
Key considerations
- Non-Negotiable Step: Even if SPF or DKIM authentication individually pass, DMARC will fail if the critical identifier alignment between the 'From' header and the authenticated domain is not met.
- Combating Impersonation: Identifier alignment directly addresses email impersonation by validating that the sender displayed to the recipient is genuinely linked to the domain that passed authentication, thereby building trust.
- Simplifying the Concept: When explaining DMARC passing, emphasize that it means both a successful SPF or DKIM check and a visible 'From' domain that clearly matches the authenticated domain.
Technical article
Documentation from DMARC.org explains that for DMARC to pass, an email must pass either SPF or DKIM authentication, and the domain used in that authentication must "align" with the domain in the visible "From:" header. This alignment ensures the sender shown to the user is the one being authenticated.
24 Jun 2023 - DMARC.org
Technical article
Documentation from Google Workspace Admin Help explains that DMARC passes when a message successfully authenticates via SPF or DKIM, and crucially, the domain in the "From" header (the RFC5322.From domain) aligns with the domain used for SPF (RFC5321.MailFrom) or DKIM (DKIM-Signature's d= tag). Alignment can be strict or relaxed, determining how exact the domain match must be.
12 Apr 2024 - Google Workspace Admin Help
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