Summary
Klaviyo DKIM signs the List-Unsubscribe header for several reasons, broadly categorized as compliance, security, and deliverability. Compliance involves meeting requirements set by RFC8058 (when implemented), "Yahoogle" (Yahoo & Google), and other email standards. Security is enhanced by preventing malicious actors from modifying the header, protecting against DKIM replay attacks, and generally maintaining the integrity of the unsubscribe process. Deliverability is improved by building trust with mailbox providers, confirming sender identity, reducing spam complaints, improving inbox placement, and complying with anti-spam regulations. Overall, DKIM signing the List-Unsubscribe header signifies a commitment to a secure and trustworthy email experience.
Key findings
- Compliance Drivers: DKIM signing is often a requirement per RFC8058 and "Yahoogle" initiatives.
- Security Benefits: It prevents header modification, protects against replay attacks, and ensures unsubscribe process integrity.
- Deliverability Gains: DKIM signing boosts trust, improves inbox placement, and lowers spam complaints.
- Enhanced Authentication: Provides a solid email authentication framework crucial for reaching intended recipients.
- Industry Best Practice: Considered a best practice, independent of specific requirements, for robust email programs.
Key considerations
- RFC 8058 Compliance: Ensure correct implementation if using the associated List-Unsubscribe method.
- Threat Mitigation: Regularly monitor and adapt email security practices to prevent evolving attack vectors.
- Reputation Management: Consistently monitor and improve sender reputation for optimal engagement and inbox delivery.
- Authentication Stack: Implement a layered approach to email authentication including SPF, DKIM and DMARC.
- Evolving Standards: Stay current with changing guidelines and requirements from mailbox providers like Gmail and Yahoo.
What email marketers say
7 marketer opinions
Klaviyo DKIM signs the List-Unsubscribe header primarily for two key reasons: compliance with RFC8058 (when implemented) and ensuring the integrity of the unsubscribe process. DKIM signing protects the List-Unsubscribe header from tampering or modification by malicious actors, preventing redirection of unsubscribe requests. This practice is considered a best practice that builds trust with recipients and mailbox providers, confirms sender identity, improves email deliverability, and helps maintain a secure and reliable unsubscribe process, ultimately reducing the risk of spam complaints and improving inbox placement.
Key opinions
- RFC Compliance: DKIM signing of the List-Unsubscribe header is required per RFC8058 if implementing that specific unsubscribe method.
- Integrity Protection: DKIM signing ensures the integrity of the List-Unsubscribe header, preventing attackers from modifying it.
- Trust Building: DKIM signing builds trust with recipients and mailbox providers, indicating a commitment to a secure and reliable unsubscribe process.
- Improved Deliverability: DKIM signing improves email deliverability by confirming sender identity and increasing the likelihood of emails reaching the inbox.
- Spam Reduction: DKIM signing reduces the risk of spam complaints, which enhances sender reputation and email performance.
Key considerations
- Implementation: Ensure correct implementation of RFC8058 if you plan to use DKIM signing for List-Unsubscribe headers.
- Security: DKIM signing helps protect against malicious actors modifying the List-Unsubscribe header for nefarious purposes.
- Reputation: Proper DKIM signing enhances sender reputation, leading to higher engagement rates.
- Deliverability Impact: The positive effects of DKIM signing on deliverability should be considered when assessing email marketing strategies.
- Compliance: Adherence to anti-spam regulations and best practices regarding unsubscribe mechanisms are facilitated by DKIM signing.
Marketer view
Email marketer from GlockApps explains that DKIM signing the List-Unsubscribe header helps improve inbox placement by demonstrating to mailbox providers that the sender is committed to providing a safe and trustworthy email experience. This can lead to higher engagement rates and better overall email performance.
13 Feb 2024 - GlockApps
Marketer view
Email marketer from Litmus explains that DKIM authentication, including signing of the List-Unsubscribe header, improves email deliverability rates by confirming the sender's identity and assuring mailbox providers that the email is legitimate. This reduces the likelihood of emails landing in the spam folder.
24 Jun 2021 - Litmus
What the experts say
3 expert opinions
Klaviyo DKIM signs the List-Unsubscribe header due to a combination of factors: It is a requirement driven by newer initiatives like the "Yahoogle" requirements, and it aligns with RFC specifications and industry best practices. Furthermore, DKIM signing protects against potential security threats, such as DKIM replay attacks, where malicious actors could manipulate the header.
Key opinions
- Yahoogle Requirement: The List-Unsubscribe header must be DKIM signed to comply with new requirements imposed by Yahoo and Google.
- Deliverability Benefit: DKIM signing is considered a general best practice that improves deliverability, regardless of specific requirements.
- Security Against Replay Attacks: Without DKIM signing, the List-Unsubscribe header can be vulnerable to DKIM replay attacks, allowing manipulation by attackers.
- RFC Compliance: DKIM signing of the List-Unsubscribe header is often required by RFC specifications.
Key considerations
- Proactive Implementation: Implement DKIM signing of the List-Unsubscribe header even if not immediately required for all situations, due to the positive impact on deliverability and security.
- Security Awareness: Be aware of the potential risks of DKIM replay attacks and ensure proper DKIM signing to mitigate these risks.
- Staying Updated: Stay updated on changing email deliverability requirements from major mailbox providers (e.g., Yahoo, Google) and adhere to RFC specifications.
Expert view
Expert from Spam Resource explains that the recent webinar covers everything about list-unsub, including RFCs and DKIM header requirements. This addresses the 'why' behind DKIM signing the List-Unsubscribe header – it's often a requirement from specifications and best practices.
5 Jul 2021 - Spam Resource
Expert view
Expert from Email Geeks shares that without DKIM signing the List-Unsub header, someone could modify the header to trick people into sending a sign of life via DKIM replay.
16 May 2022 - Email Geeks
What the documentation says
3 technical articles
Klaviyo, like other email senders, DKIM signs the List-Unsubscribe header to comply with RFC 8058 (when implemented) and to enhance email security and deliverability. DKIM signing prevents malicious actors from modifying or spoofing the header. This strengthens the overall email authentication framework, building trust with mailbox providers (like Gmail and Microsoft) and reducing the risk of emails being flagged as spam, ultimately leading to improved engagement.
Key findings
- RFC 8058 Compliance: RFC 8058 mandates DKIM signing of the List-Unsubscribe header when implemented according to the standard.
- Security Enhancement: DKIM signing prevents modification and spoofing of the List-Unsubscribe header, protecting against malicious activities.
- Improved Deliverability: Robust authentication, including DKIM, is essential for achieving good deliverability, especially with major providers like Gmail.
- Trust Building: DKIM signing helps build trust with mailbox providers and recipients, signaling that the email is legitimate and the sender is responsible.
- Phishing Prevention: DKIM signing of critical headers, like List-Unsubscribe, helps prevent phishing and spoofing attempts.
Key considerations
- RFC Implementation: Ensure that the List-Unsubscribe header is implemented correctly according to RFC 8058 if you intend to use DKIM signing.
- Comprehensive Authentication: Implement a comprehensive email authentication strategy that includes DKIM, SPF, and DMARC for best results.
- Security Audits: Regularly audit your email security practices to ensure ongoing protection against emerging threats.
- Compliance Monitoring: Stay up-to-date with the latest email authentication and deliverability guidelines from major mailbox providers.
- Reputation Management: Monitor your sender reputation and take steps to address any issues promptly.
Technical article
Documentation from Google explains that robust authentication, including DKIM, is crucial for ensuring deliverability to Gmail users. Signing all relevant headers, including List-Unsubscribe, enhances trust and reduces the risk of emails being marked as spam.
9 Nov 2021 - Google
Technical article
Documentation from RFC Editor specifies that if the List-Unsubscribe header is implemented according to RFC 8058, it SHOULD be signed using DKIM to prevent modification or spoofing by malicious actors.
7 Jun 2024 - RFC Editor
Can DKIM be set up on a subdomain, and which domain should be used for signing?
Does the DKIM domain need to align with the List-Unsubscribe domain?
How can I verify if my company's emails have List-Unsubscribe headers correctly configured?
How do I find the DKIM selector for my domain in Dmarcian or Hubspot?
How to troubleshoot DKIM failures and which tools to use?
Should I include List-Unsubscribe headers in transactional emails and what are the DKIM best practices?
