This option works only if you have rebuilt the mail server in cwp.admin with antispam.
You can blacklist or whitelist incoming emails in the following files:
After making changes you need to run the following command for the files you edited
postmap /etc/postfix/sender_blacklist postmap /etc/postfix/sender_whitelist
# Example for blacklisting domains/IP's or emails, one per line:
188.8.131.52 REJECT 184.108.40.206 REJECT mail.freemailer.tld REJECT We don't allow emails from mail.freemailer.tld email@example.com REJECT
After REJECT you can add the message which will be returned to the sender.
The whitelist is the same only difference is that instead of REJECT you use OK.
Example for whitelisting domains/IP's, one per line:
220.127.116.11 OK 18.104.22.168 OK mail.freemailer.tld OK firstname.lastname@example.org OK