1. Select the Leaf level to which you want to add your custom domains.
2. Select the Custom rules tab.
3. Click Add custom rules.
4. Add the domains that you want to block. When adding multiple domains, separate them using commas.
5. Choose the platforms and interfaces on which these domains should be blocked.
6. Select Block in the the Policy action column.
7. Click Add and close.
8. Click Save and apply.