Francesc Pe?alvez: > Lately we are receiving spam mails that apparently the mail from the and > the to is the same. How is it possible to avoid this?. I have configured > postfix to avoid the relay of emails and to be able to send mail through > my postfix is necessary the auth , these emails are sent externally from > several ips and seeing the logs of those emails are not authenticated
Postfix 3.0 and later: /etc/postfix/main.cf: smtpd_sender_restrictions = permit_mynetworks permit_sasl_authenticated check_sender_access inline:{ { example.com = REJECT local sender from unauthorized client } { other.example = REJECT local sender from unauthorized client } } Instead of example.com and other.example, specify your email domains. Note: this breaks email from remote mail forwarders or from remote distribution lists that don't reset the sender address. Wietse