Block User From Sending Email

I see this post, but not work.. there're older and a think best option put a new post.

How Do I Block One Domain From Sending Email From My Server?

Advance editor
Section Config
domainlist blocked_domains : lsearch;/etc/blockedsenderdomains


Section: ROUSTART
reject_domains:

driver = redirect
# RBL Blacklist incoming hosts
domains = blocked_domains
allow_fail
data = :fail: Connection rejected: SPAM source $domain is manually blacklisted.

File /etc/blockedsenderdomains contain domain I like block for send domain.

Restart exim, etc...

But of any put exploit or php file when mail function.

I think it's because sender (php fastcgi) it's users system and not domain.

How I can to block a user sender?