Spam Assassin in Cpanel

Spam Assassin

You can set email rule, such as blacklist and whitelist email addressess and domains with Spam Assassin.

To blacklist email addresses or domains,
1) Open Cpanel >Spam Assassin >Configure Spam Assassin
2) Look for blacklist_from
3) Add addresses or domains to each text field
This will block this email address.

This will block this entire domain.