What is SMTP Discovery?
SMTP Discovery, as part of the Advanced Email Security service, is a feature that takes note of addresses that are sent mail on the domain name, that are not already added as users or functional accounts in Proofpoint. SMTP Discovery automatically discovers these users and provides the option to add to the organization or mark as an invalid address.
You may receive an SMTP Discovery Warning Report from Proofpoint via email. This report informs you of actions you need to take to add users and distribution lists to the encryption service.
If no action is taken within 4 weeks of receiving the report, it could impact mail flow for the affected email addresses.
An SMTP Discovery Warning Report is sent by email; an example is provided below: