Office 365 How To Configure External Collaboration Settings with Domain Restrictions

In Office 365, how do you configure external collaboration settings but restrict certain domains from collaboration.

This is all configured under Azure Active Directory Admin Center.

A few clicks and your configured

User settings> External Collaboration Settings > Set the level of restrictions and Save. This example is restricting collaboration with *.outlook.com and *.hotmail.com domains

or if security if a higher priority over flexibility, Disable Members and Guests invite and set “Allow invitations only to the specified domains” Example :