Proxy server to filter all external MX incoming emails!

Hello,

How does it take to configure the SMTP server to reject all mail that does not come from an external server dedicated.

Explanation:

I would use a proxy server to filter all external MX incoming emails.

I'm stuck because I do not know or configure it.

Thank you for your help.

Sincerely,

 

Hello,

I replied, hoping that this is ok.

I modified the file "master.cf"as follows:

smtpd_helo_restrictions= permit_mynetworks, warn_if_reject reject_non_fqdn_hostname, reject_invalid_hostname, reject

and I add the proxy server name MX section "network" in the file "main.cf" as follows:

mynetworks = 127.0.0.0/8 [::1]/128, my_serverproxymx

thank you let me know if this is correct.

Sincerely,