SMTP Open Relay probléma

Sziasztok!

Van 1 kis problémám. A postfix szerverünk a log szerint néha kéri a hitelesítést néha nem, a spammereket is átengedi de nem mindet csak 10-ből 3-at de azt hitelesítés nélkül.

# See /usr/share/postfix/main.cf.dist for a commented, more complete version


smtpd_banner = $myhostname ESMTP $mail_name (Debian/GNU)
biff = no

# appending .domain is the MUA's job.
append_dot_mydomain = no

# Uncomment the next line to generate "delayed mail" warnings
#delay_warning_time = 4h

mydomain = xxx.hu
myhostname = debian.xxx.hu
alias_maps = hash:/etc/aliases
alias_database = hash:/etc/aliases
myorigin = /etc/mailname
mydestination = debian.xxx.hu, localhost.xxx.hu, localhost
relayhost =
#relaydomains= $mydestination
mynetworks = 127.0.0.0/8
mailbox_command = procmail -a "$EXTENSION"
mailbox_size_limit = 0
recipient_delimiter = +
inet_interfaces = all
smtpd_sasl_local_domain =
smtpd_sasl_auth_enable = yes
smtpd_sasl_security_options = noanonymous
broken_sasl_auth_clients = yes
smtpd_recipient_restrictions = permit_sasl_authenticated,permit_mynetworks,reject_unauth_destination
smtpd_sender_restrictions = reject_unknown_sender_domain
smtpd_tls_auth_only = no
smtp_use_tls = yes
smtpd_use_tls = yes
smtp_tls_note_starttls_offer = yes
smtpd_tls_key_file = /etc/postfix/ssl/smtpd.key
smtpd_tls_cert_file = /etc/postfix/ssl/smtpd.crt
smtpd_tls_CAfile = /etc/postfix/ssl/cacert.pem
smtpd_tls_loglevel = 1
smtpd_tls_received_header = yes
smtpd_tls_session_cache_timeout = 3600s
tls_random_source = dev:/dev/urandom
home_mailbox = Maildir/
local_recipient_maps =
virtual_maps = hash:/etc/postfix/virtusertable
mydestination = /etc/postfix/local-host-names
disable_dns_lookups = no
smtpd_helo_required=yes

Ezeket a beállításokat használom. Van valaki valami 5lete?
Köszönöm
Gili