Лучше main.cf полностью покажу:
mynetworks = localhost, $myhostname, $mydomain, $config_directory/mynetworks
smtpd_sasl_type = dovecot
smtpd_sasl_path = private/auth
smtpd_sasl_auth_enable = yes
broken_sasl_auth_clients = yes
smtpd_reject_unlisted_sender = yes
smtpd_reject_unlisted_recipient = yes
smtpd_use_tls = no
smtpd_tls_key_file = /var/lib/ssl/private/postfix.key
smtpd_tls_cert_file = /var/lib/ssl/certs/postfix.cert
soft_bounce = no
smtpd_helo_required = no
smtpd_helo_restrictions = check_recipient_access cdb:/etc/postfix/whitelist, permit_sasl_authenticated, reject_unknown_hostname, permit_mynetworks, check_helo_access cdb:/etc/postfix/helo_access, reject_non_fqdn_hostname, reject_invalid_hostname, reject_rbl_client sbl.spamhaus.org, reject_rbl_client zen.spamhaus.org, reject_rbl_client dnsbl.ahbl.org, permit
smtpd_client_restrictions = check_recipient_access cdb:/etc/postfix/whitelist, permit_sasl_authenticated, permit_mynetworks, check_client_access cdb:/etc/postfix/client_access, reject_rbl_client xbl.spamhaus.org, permit
smtpd_sender_restrictions = check_recipient_access cdb:/etc/postfix/whitelist, reject_unknown_sender_domain, permit_sasl_authenticated, permit_mynetworks, check_sender_access cdb:/etc/postfix/sender_access, permit
smtpd_recipient_restrictions = check_recipient_access cdb:/etc/postfix/recipient_access, permit_sasl_authenticated, reject_non_fqdn_recipient, reject_unknown_recipient_domain, reject_invalid_hostname,reject_unauth_destination, reject_rbl_client sbl.spamhaus.org, reject_rbl_client zen.spamhaus.org, reject_rbl_client dnsbl.ahbl.org, permit
smtpd_data_restrictions = reject_unauth_pipelining, permit
#virtual_alias_maps = ldap:/etc/postfix/ldap-aliases.cf, ldap:/etc/postfix/ldap-users.cf
local_recipient_maps = proxy:unix:passwd.byname $alias_maps ldap:/etc/postfix/ldap-users.cf
mailbox_unpriv_delivery = no
#relayhost = false
mailbox_size_limit = 0
message_size_limit = 20971520
smtpd_sasl_security_options = noanonymous
