How should I roll out DMARC enforcement while considering forwarded emails and DKIM issues?

Email marketer from Proofpoint advises that when dealing with DMARC enforcement, you must properly authenticate third-party senders, i.e., include them in your SPF record or have them sign with DKIM using your domain. They suggest working closely with these vendors to ensure they comply with DMARC requirements.

Marketer from Email Geeks suggests that Google Calendar invites should not cause DMARC issues if Google Workspace DKIM is correctly implemented. SPF alignment may break because Google overwrites the Return-Path.

Marketer from Email Geeks recommends focusing on resolving DKIM issues first, as they significantly contribute to DMARC failures. He also advises starting with a Quarantine policy instead of immediately enforcing Reject, monitoring reports for 1-2 weeks.

Marketer from Email Geeks explains that enabling DMARC with an enforcing policy may break forwarding, preventing messages from reaching the inbox. DMARC is designed to fail if a message is automatically forwarded (breaking SPF alignment) and modified (breaking DKIM alignment), a risk that must be accepted when deploying DMARC.

Email marketer from SparkPost emphasizes ensuring proper DKIM signing for all email sources, including third-party senders, before enforcing DMARC. This includes verifying that DKIM records are correctly set up and that emails are properly signed with the correct domain.

Marketer from Email Geeks says that seeing gappssmtp.com indicates the absence of a customized DKIM signature, which is the core issue.

Email marketer from EmailGeeks forum user recommends carefully setting up DKIM records. You should generate a DKIM key, add the public key to your DNS records, and ensure that your email sending server is configured to sign outgoing emails with the corresponding private key. This ensures that your emails are authenticated and pass DMARC checks.

Marketer from Email Geeks explains that unknown sources in DMARC reports are often legitimate forwarding, where a recipient domain automatically forwards emails, breaking SPF and possibly DKIM alignment. The forwarding destination then generates the DMARC report.

Email marketer from Valimail explains the DMARC policy stages, starting with 'p=none' for monitoring without impact, then 'p=quarantine' to direct failing messages to the spam folder, and finally 'p=reject' to instruct receivers to block non-compliant emails, stressing the importance of iterative adjustments based on monitoring.

Marketer from Email Geeks mentions the DMARC failures are related to not using a custom DKIM signing domain.

Email marketer from SendGrid explains that to mitigate forwarding issues, consider using a Sender Policy Framework (SPF) flattening service or implement the Authenticated Received Chain (ARC). SPF flattening reduces the number of DNS lookups, while ARC helps preserve authentication information across multiple forwarding hops.

Email marketer from EasyDMARC explains that to handle forwarding issues, one should consider implementing ARC (Authenticated Received Chain) to preserve authentication results across forwarding hops, and also recommends educating users about the impact of forwarding on DMARC.

Email marketer from Reddit suggests a phased approach to DMARC implementation, recommending starting with a 'p=none' policy to monitor email traffic, then moving to 'p=quarantine' to filter failing emails, and finally 'p=reject' once confident in the configuration. Addresses DKIM issues before DMARC is fully enforced. Also advises setting up aggregate reports to monitor for unauthorized use of your domain.

Email marketer from Mailjet shares a guide for implementing DMARC that recommends starting with a 'p=none' policy to gather data through DMARC reports, then progressing to 'p=quarantine' to send failing emails to spam, and finally to 'p=reject' to block unauthorized emails, emphasizing careful monitoring at each stage.

Email marketer from MXToolbox recommends using their DMARC record lookup tool to check for any errors in your DMARC record. This tool can help identify syntax errors, incorrect tags, or missing information that can cause DMARC to fail. Correcting these errors is essential before enforcing DMARC.

Expert from Spam Resource explains the importance of proper SPF and DKIM setup prior to implementing a DMARC policy and suggests deploying DMARC in stages, starting with a monitoring policy (p=none) to assess the impact and identify legitimate sending sources before moving to quarantine or reject policies.

Expert from Word to the Wise explains that DMARC failures occur with forwarding because the original SPF and DKIM records don't match. She suggests implementing ARC (Authenticated Received Chain) and BIMI to build trust and manage brand visibility. Also, start with 'p=none' to gather data before enforcing stricter policies.

Documentation from Microsoft explains how to configure DKIM for your custom domain in Microsoft 365. This involves generating DKIM keys, adding CNAME records to your DNS settings, and enabling DKIM signing for your domain. Proper DKIM implementation ensures that your emails are authenticated and pass DMARC checks.

Documentation from DMARC.org suggests using the Authentication-Results header and ARC (Authenticated Received Chain) to handle forwarded emails. These mechanisms allow receiving servers to validate the authentication status of forwarded messages, mitigating DMARC failures due to forwarding.

Documentation from Google Workspace Admin Help explains that to roll out DMARC enforcement, start by setting up SPF and DKIM, monitor DMARC reports to identify legitimate email sources, and gradually increase the DMARC policy from 'p=none' to 'p=quarantine' and finally to 'p=reject' to minimize disruptions.

Documentation from RFC Editor explains that DMARC is designed to work in conjunction with SPF and DKIM to authenticate email and provides mechanisms for handling authentication failures, including those caused by forwarding. The document also specifies how receivers should handle DMARC policies.