Sometimes organization prefer to block (or) mark as spam Emails coming from .EU or .ME domains, Below are the steps to block any domains based on domain extensions. Example : doing this would block any mails coming from email@example.com, firstname.lastname@example.org etc...
- Access Exchange admin center.
- Navigate to mail flow > rules.
- Click the plus icon to create a new rule.
- In the pop up window, click More options.
- Configure the rule according to the screenshot:
.eu$ is a RegEx pattern which matches with email@example.com, firstname.lastname@example.org.. etc..