i am using postfix - dovecot based mail system and i have my own frontend - backend api structure for send and recieve mails. I am slightly new on postfix and i want to do something like;
I have an domain as abc.com and i want to some users on this domain only can send mail on my local domains and others send mail inside and outside as normal. Is it possible to do that in postfix or am i must do something on my api backend side?