Postfix Whitelist before recipient restrictions

If you do processing based on RCPT TO address, you are going to flood this person with spam, because it will disable any further spam checks.

Your only option is to use check_sender_access.

smtpd_recipient_restrictions =
            check_client_access hash:/etc/postfix/access_sender
            reject_unauth_destination,
            reject_rbl_client b.barracudacentral.org,
            reject_rbl_client cbl.abuseat.org,
            reject_rbl_client bl.mailspike.net,
            check_policy_service unix:postgrey/socket

Like so:

[email protected]      OK
domain.com               OK
fromuser@                OK

dont forget to postmap access_sender after you create it.