How to discard emails using the sender email address in Postfix

MTA

Postfix

Make list of email address/domains you wish to discard vi /opt/csw/etc/postfix/sender_access

   sender@example.com DISCARD
   DoNotReply@spam.example.com DISCARD
   subdomain.example.com DISCARD

Hash table the file

   /opt/csw/sbin/postmap dbm:/opt/csw/etc/postfix/sender_access

Add into the postfix config the smtp restriction line in

   vi /etc/opt/csw/postfix/main.cf

smtpd_sender_restrictions = check_sender_access dbm:/opt/csw/etc/postfix/sender_access