The following steps begin with logging into https://admin.exchange.microsoft.com with credentials authorized to make enterprise-wide email configuration changes.
DKIM / DMARC Validation
Create Basic Connector
In the Exchange admin center (https://admin.exchange.microsoft.com/#/connectors), navigate to Mail Flow -> Connectors, and click on “Add a connector”
Configured your connector as a “Partner Organization”:
Name the connector “PhishProtection Inbound”, and optionally add notes:
When prompted, enter just add one of our IPs, you will be adding the rest once you configure the enhanced connector. ( https://support.duocircle.com/support/solutions/articles/5000524218-ip-addresses-for-firewalls):
Accept the remaining defaults to complete adding the connector:
Upgrade to Enhanced Connector
Once the connector is saved, visit https://security.microsoft.com/skiplisting, to upgrade the connector to an Enhanced Connector.
Click on the connector, and under “IP addresses to skip”, enter all of the IPs found at https://support.duocircle.com/support/solutions/articles/5000524218-ip-addresses-for-firewalls
Notes
Enhanced IP Filtering for Connectors https://protection.office.com/skiplisting
https://support.phishprotection.com/support/solutions/articles/5000863172-enhanced-filtering-for-connectors-in-365
Get this page onto the site - https://support.duocircle.com/support/solutions/articles/5000524218-ip-addresses-for-firewalls
More information about connectors
https://learn.microsoft.com/en-us/exchange/mail-flow-best-practices/manage-mail-flow-using-third-party-cloud