How to block incoming email
I have a postfix server in my office runnning in centos
My obbjective is to have one domain name to be used in our internal and external email communication
Some users are permitted to send and recieve coming from outside (External and Internal)
and some users are permitted only internal
so if the user attempt to send outside and with no permission the server will blocked it because its only internal and that was so good.
and this is my question even internal permission has capable to receive email coming from outside or other domain name. Is there a way to block it all incoming if the user are internal permission only.