DMARC (Domain-based Message Authentication, Reporting, and Conformance) provides several policy settings that define how receiving email servers should handle emails that fail DMARC authentication. Here are the different DMARC policy settings and their impact on email deliverability:
"p=none": The policy setting "p=none" indicates that no specific action should be taken on emails that fail DMARC authentication. It allows the domain owner to monitor email authentication results and receive reports without impacting the delivery of emails.
Impact on deliverability: "p=none" does not directly impact email deliverability. However, it provides visibility into email authentication issues and helps in making informed decisions regarding DMARC enforcement.
"p=quarantine": With the "p=quarantine" setting, emails that fail DMARC authentication are treated as suspicious, and receiving email servers may deliver them to the recipient's spam or junk folder.
Impact on deliverability: "p=quarantine" can have a moderate impact on email deliverability. While some email servers may move failed emails to spam folders, others may still deliver them to the inbox. The exact impact depends on the recipient's email provider and settings. Monitoring DMARC reports and adjusting the policy can help minimize false positives and improve deliverability.
"p=reject": When the policy is set to "p=reject," emails that fail DMARC authentication are not accepted by receiving email servers. They are typically rejected and not delivered to the recipient's inbox.
Impact on deliverability: "p=reject" has the highest impact on email deliverability. If an email fails DMARC authentication, it is likely to be rejected and not delivered to the recipient. Implementing "p=reject" without careful configuration and monitoring can result in legitimate emails being blocked. It's important to gradually transition to "p=reject" while closely monitoring DMARC reports and making necessary adjustments.
"p=quarantine, "p=reject" (percentage-based): In addition to the above settings, DMARC allows specifying a percentage of emails to be subjected to quarantine or reject actions. For example, "p=quarantine 50%" or "p=reject 10%". These settings allow a gradual enforcement approach to minimize false positives and gradually improve email authentication.
Impact on deliverability: The impact on deliverability depends on the percentage specified. With a lower percentage, the impact is limited, and more emails will be delivered to the inbox. As the percentage increases, the impact on deliverability becomes more significant, potentially moving a larger proportion of failed emails to spam or rejecting them altogether.
It's important to note that the impact on deliverability is not solely determined by the DMARC policy setting. Other factors such as the reputation of the sending IP address, content quality, and recipient engagement also play a significant role. It is recommended to gradually implement stricter DMARC policies while monitoring and adjusting based on the reports received.