Oct 17 09:21:40 debian postfix/smtpd[1643]: NOQUEUE: reject: RCPT from
unknown[x.x.x.x]: 553 5.7.1 <sender@example.com>: Sender address rejected:
not owned by user sender@example.com; from=<sender@example.com>
to=<receiver@gmail.com> proto=ESMTP helo=<[192.168.1.5]>

relay_domains = *

smtpd_sender_restrictions =
    permit_mynetworks,
    permit_sasl_authenticated

smtpd_relay_restrictions =
    permit_mynetworks,
    permit_sasl_authenticated,
    reject_unauth_destination

smtpd_recipient_restrictions =
    permit_mynetworks,
    permit_sasl_authenticated,
    reject_unauth_destination,
    reject_rbl_client zen.spamhaus.org,
    reject_rhsbl_reverse_client dbl.spamhaus.org,
    reject_rhsbl_helo dbl.spamhaus.org,
    reject_rhsbl_sender dbl.spamhaus.org,

smtpd_data_restrictions = reject_unauth_pipelining

submission inet n       -       -       -       -       smtpd
    -o smtpd_tls_security_level=encrypt
    -o smtpd_sasl_security_options=noanonymous
    -o smtpd_client_restrictions=permit_sasl_authenticated
    -o smtpd_sender_restrictions=reject_sender_login_mismatch

virtual_mailbox_maps    = mysql:/etc/postfix/mysql-virtual-mailbox-maps.cf
smtpd_sender_login_maps = mysql:/etc/postfix/mysql-virtual-mailbox-maps.cf

# good
query = SELECT email FROM postfix_mailbox_maps where email = '%s';

# bad
query = SELECT 1 FROM postfix_mailbox_maps where email = '%s';

virtual_alias_maps = hash:/etc/postfix/virtual
virtual_mailbox_domains = hash:/etc/postfix/virtual-mailbox-domains
virtual_mailbox_maps = hash:/etc/postfix/virtual-mailbox-users

sender@exemple.com    sender@exemple.com
other@exemple.com     other@exemple.com
alias@exemple.com     sender@exemple.com

exemple.com    OK

sender@exemple.com    sender@exemple.com
other@exemple.com     other@exemple.com