Setting up DMARC (Domain-based Message Authentication, Reporting, and Conformance) involves configuring DNS records for your domain to help protect against email spoofing and phishing. DMARC works in conjunction with SPF (Sender Policy Framework) and DKIM (DomainKeys Identified Mail). Here are the general steps to set up DMARC:
- Understand DMARC: Familiarize yourself with DMARC and its components, including SPF and DKIM. DMARC allows you to specify how email receivers should handle messages that don’t align with SPF and DKIM.
- Configure SPF and DKIM: Ensure that your domain has SPF and DKIM configured. SPF helps to validate the sender’s IP address, while DKIM adds a digital signature to your emails. Both mechanisms contribute to the overall email authentication process.
- Create a DMARC Policy: Create a DMARC TXT record in your DNS settings. This record informs email receivers about your DMARC policy and how they should handle messages that fail SPF and DKIM checks.The DMARC TXT record usually looks like this:
v=DMARC1; p=quarantine; rua=mailto:dmarc@example.com; ruf=mailto:dmarc@example.com; sp=quarantine; adkim=s; aspf=s;
v=DMARC1
: Indicates that this is a DMARC record.p=quarantine
: Specifies the policy for messages that fail authentication. Other options include “none” (take no action) and “reject” (discard the message).rua=mailto:dmarc@example.com
: Specifies the email address to which aggregate reports (summaries of DMARC activity) should be sent.ruf=mailto:dmarc@example.com
: Specifies the email address to which forensic reports (detailed information about failed authentication) should be sent.sp=quarantine
: Specifies the policy for subdomains.adkim=s
: Specifies that DKIM should be aligned (the domain in the DKIM signature matches the From: header domain).aspf=s
: Specifies that SPF should be aligned (the domain in the SPF record matches the From: header domain).
- Implement DMARC Gradually: Start with a DMARC policy of
p=none
initially, which allows you to monitor and collect reports without impacting the delivery of emails. Once you are confident that legitimate emails are passing authentication checks, you can gradually adjust your DMARC policy top=quarantine
orp=reject
. - Monitor Reports: Regularly check the DMARC reports to understand how your emails are being handled by different email providers. Use this information to fine-tune your DMARC policy and improve email deliverability.
- Adjust and Iterate: Based on the reports and feedback, make necessary adjustments to your SPF, DKIM, and DMARC configurations. The goal is to achieve a balance between email security and deliverability.
- Documentation and Communication: Document your DMARC policy and configurations. Communicate any changes to your team, especially if you plan to move from a monitoring policy (
p=none
) to a more restrictive policy (p=quarantine
orp=reject
).