Plesk Postfix configuration allows authenticated users to use any sender address

[philippL]

I was trying to block incoming emails that use our own domains as the FROM address. I found this link: http://serverfault.com/questions/688758/reject-incoming-emails-that-use-your-own-domain-as-sender. Then I noticed this part in the default Plesk postfix configuration:

smtpd_sender_restrictions = check_sender_access hash:/var/spool/postfix/plesk/blacklists, permit_sasl_authenticated

There is no entry "reject_sender_login_mismatch" like the one in the article. This means I can use any FROM address I'd like - even from foreign domains! According to the postfix documentation I need to set "$smtpd_sender_login_maps" - but I have no clue how to configure that correctly in Plesk. Does anyone know how?

And does changing this break PHP scripts using the "mail" function (or local sendmail)?