Does the DKIM domain need to align with the List-Unsubscribe domain?
Summary
What email marketers say10Marketer opinions
Email marketer from Mailjet explains that while alignment isn't strictly enforced, it's a good practice for deliverability. Having consistent domains builds trust with mailbox providers.
Marketer from Email Geeks shares that the DKIM and the List-unsubscribe do not have to align. The main requirements are A valid DKIM Signature and `List-Unsubscribe` and `List-Unsubscribe-Post` in the `h=`
Email marketer from Reddit mentions that while not technically mandatory, aligning DKIM and List-Unsubscribe domains can help improve deliverability rates, especially with stricter mailbox providers like Gmail and Yahoo.
Email marketer from EmailDeliverabilityForum.com suggests that aligning DKIM with the List-Unsubscribe domain is a 'best practice' to help legitimize your email and reduce the chance of being flagged as spam.
Email marketer from StackOverflow explains that while not mandatory, having the DKIM domain align with the List-Unsubscribe domain can help improve sender reputation and trustworthiness.
Email marketer from Email Vendor Guide notes that although alignment isn't a hard requirement, it strengthens sender authentication, which can positively influence placement rates, especially when combined with other authentication methods like SPF and DMARC.
Email marketer from GlockApps advises using testing tools to verify email authentication, including DKIM. Domain alignment assists with getting a higher score in deliverability tests.
Email marketer from Quora states that aligning DKIM and List-Unsubscribe domains is a good practice, and though not strictly enforced by all providers, it can contribute to a better sender reputation.
Email marketer from SendPulse explains that proper domain authentication is important for getting your emails delivered, including DKIM, SPF, and DMARC. Whilst List-Unsubscribe isn't mentioned specifically, its a clear alignment across domains helps.
Email marketer from Litmus notes that email authentication is key to email deliverability success and that there are tools to test for this.
What the experts say4Expert opinions
Expert from Word to the Wise discusses how email authentication is a complex issue and domain keys are one small component. She states that while domain alignment might help, its a small part of a larger piece.
Expert from Email Geeks clarifies that if you change the content between the time the message is signed and when the signature is checked then dkim will fail.
Expert from Email Geeks explains that The two list-unsubscribe headers must be signed with dkim and that the domains do not need to align.
Expert from Spam Resource explains the usage of list-unsubscribe headers for compliance and improved deliverability, and that it is more important to have a clear and working unsubscribe process.
What the documentation says4Technical articles
Documentation from DMARC.org focuses on SPF and DKIM alignment for domain-based message authentication, reporting, and conformance (DMARC), and recommends DKIM alignment for better email security and deliverability.
Documentation from SparkPost highlights that DKIM alignment improves deliverability and sender reputation. Though a direct requirement for List-Unsubscribe domain alignment isn't stated, consistent domain usage is encouraged.
Documentation from DKIM.org describes the technical specifications of DKIM but doesn't specify requirements for alignment with other email headers like List-Unsubscribe.
Documentation from RFC Editor specifies the format and usage of the List-Unsubscribe header field in email messages, but doesn't explicitly require alignment between the DKIM domain and the List-Unsubscribe domain.