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How to ask your vendor to send DMARC-compliant email on your behalf

How to ask your vendor to send DMARC-compliant email on your behalf

DeploymentTechnical Guidance

The dmarcian team categorizes the sources we see our customers use and include resources that assist in configuring sources to send DMARC-compliant email. Sometimes, however, we are unable to find any publicly available documentation on how to achieve DMARC compliance for a particular source—a service that sends email on behalf of another domain. In these cases, the customer must reach out to the source, or vendor, to request assistance.

“Not all third-party providers officially support DMARC, and their first response may be negative,” says Ash Morin, dmarcian’s Director of Deployment. “However, the reality is that they may simply not understand the scope of the request. In our experience, a service provider will often find out that they are in fact capable of supporting DMARC once the requirements are explained clearly to them.”

If you find yourself in a situation where you need to contact a source but don’t know what to ask, here’s a template to use as a starting point:

“{ORGANIZATION} is deploying DMARC, and we’ve discovered that {VENDOR} is sending email on our behalf using the {DOMAIN} email domain.

To reach DMARC compliance, SPF and/or DKIM authentication must be configured in a specific way, as described in this article:

We require alignment where the return-path domain or the DKIM signing domain match the domain you use to send on our behalf.

Can your service support DMARC-compliant authentication using our domain? If so, please let us know the best way forward to enable this configuration with your service.”

Should the source you’re contacting require more information, we also have a series of articles dedicated to explaining how sources can send DMARC-compliant email on behalf of their customers.

If the source shares configuration information with you that you think could benefit other users, feel free to send an email to; our team will review the information and update the source guidance as necessary. Additionally, you can contribute knowledge to our source guidance community on our Forum.