100% tested with CWP7Pro + Centos 7.9.2009
1. Write the tlds to be blocked to the sender_blacklist file. (/etc/postfix/sender_blacklist)
Example;
/\.asia$/ REJECT All Domain
/\.bg$/ REJECT All Domain
/\.bid$/ REJECT All Domain
/\.biz$/ REJECT All Domain
/\.br$/ REJECT All Domain
/\.buzz$/ REJECT All Domain
(...)
2. Get root access on your server;
# cd /etc/postfix
# postmap hash:/etc/postfix/sender_blacklist
# systemctl restart postfix.service
3. open the main.cf file (/etc/postfix/main.cf);
# rules restrictions
smtpd_client_restrictions = reject_unknown_client, check_client_access hash:/etc/postfix/sender_blacklist
smtpd_helo_restrictions =
smtpd_sender_restrictions =
pcre:/etc/postfix/sender_blacklist
smtpd_recipient_restrictions = check_policy_service inet:127.0.0.1:10031, permit_sasl_authenticated, permit_mynetworks, check_client_access hash:/etc/postfix/sender_whitelist, check_client_access hash:/etc/postfix/sender_blacklist, reject_unauth_destination, reject_non_fqdn_sender, reject_non_fqdn_recipient, reject_unknown_recipient_domain, reject_rbl_client zen.spamhaus.org, reject_rbl_client bl.spamcop.net
save and exit.
4. And the end;
# systemctl restart postfix.service
Goodbye, spam mails ...