Fake mails from local domain, how to block them?

tui

Well-Known Member
Jun 15, 2007
144
40
78
Mexico
cPanel Access Level
Root Administrator
Hello, i have DKIM verification, Sender Verification, SpamAssassin and others filters/blacklist enabled, but we are receiving mails from local domains users originated from remote servers, example:

On the server we have this domain user:

[email protected]

and we are receiving mails from [email protected] on [email protected] inbox, but the mails are coming from other server, however our server does not filter or reject them.

How can we filter/block mails from localusers but that originates on other servers?