Track All Senders
Using the domains you’ve entered into DMARC Protection (either directly or indirectly by publishing a DMARC p=none policy) and the information gathered from the Senders page from monitoring data for a period of time, you should be able to gather information about all third-party senders used by your organization.
An easy way to track this information is in an external spreadsheet. See Example Domain-to-Senders tracking spreadsheet for an example.
You’ll use the information in this spreadsheet to create the SPF records and DKIM keys needed for proper authentication, as well as to communicate the status of your authentication project internally.
You may discover, as shown above, that different departments in your organization are using multiple accounts at the same Sender. You may also be using senders that send for multiple system types. For example, SendGrid offers mailing services and also provides mailing infrastructure for the Freshdesk CRM service.