So the idea here is to have an email address that you would only like a select few to have access to email to, for example, a everyone or all address. In this example we will be locking down the email address all@example.com and only allow the address abc@example.com to send to it.

In /etc/postfix/main.cf add the following:

smtpd_restrictions_classes =  restricted_recipient

• note: This is in smtpd_SENDER_restrictions to avoid becoming an open relay because of the “OK” below.

smtpd_sender_restrictions =
  check_recipient_access hash:/etc/postfix/restricted_recipient

restricted_recipient =
  check_sender_access hash:/etc/postfix/privileged_sender
  reject

restricted_recipient:

all@example.com         restricted_recipient

privileged_sender:

abc@example.com         OK