Hi all,
Sometimes our mail server is 'under attack' and we get a lot of these
entries in our log file:
Aug 17 11:08:19 stevie.youngguns.nl postfix/smtpd[14890]: [ID 197553
mail.info] NOQUEUE: reject: RCPT from unknown[212.22.199.165]: 450 4.1.8
<indispensabl...@homepc>: Sender address rejected: Domain not found;
from=<indispensabl...@homepc> to=<banquetastrophys...@rpc-design.nl>
proto=ESMTP helo=<homepc>
Normally we reject about 15 msgs/min but when such an attack happens it
peaks to about 700 msgs/min. The error is returned to the sending mail
(spam) server is 450 domain not found. Because a domain lookup could
also be a temporary failure this is a temporary error returned.
The 450 error triggers the spammer to retry sending the mail.
The to address is an unknown user on my system so postfix could return a
550 error. How can I do this?
I've attached postconf -n output in main.cf.
--
Martijn de Munnik
address_verify_map = btree:${data_directory}/verify
alias_maps = hash:/opt/csw/etc/postfix/aliases
body_checks = regexp:/opt/csw/etc/postfix/maps/body_checks
broken_sasl_auth_clients = yes
command_directory = /opt/csw/sbin
config_directory = /etc/postfix
content_filter = amavisfeed:localhost:10024
daemon_directory = /opt/csw/libexec/postfix
data_directory = /opt/csw/var/lib/postfix
default_database_type = hash
delay_warning_time = 4h
disable_vrfy_command = yes
header_checks = regexp:/opt/csw/etc/postfix/maps/header_checks
home_mailbox = Maildir/
html_directory = /opt/csw/share/doc/postfix/html
inet_interfaces = all
mailbox_command = /opt/csw/bin/procmail-wrapper -o -a $DOMAIN -d $LOGNAME
mailbox_size_limit = 209715200
mailq_path = /opt/csw/bin/mailq
manpage_directory = /opt/csw/share/man
maximal_backoff_time = 8000s
maximal_queue_lifetime = 7d
message_size_limit = 20971520
mime_header_checks = regexp:/opt/csw/etc/postfix/maps/mime_header_checks
minimal_backoff_time = 1000s
mydestination = $myhostname, localhost.$mydomain
myhostname = stevie.youngguns.nl
mynetworks_style = host
myorigin = $myhostname
newaliases_path = /opt/csw/bin/newaliases
readme_directory = /opt/csw/share/doc/postfix/README_FILES
receive_override_options = no_address_mappings
recipient_delimiter = +
relay_domains = $mydestination, slagenlandwonen.nl, wfcommunicatie.nl,
gooischebrink.com, interjute.nl, melamo.nl, fair-play.nl, loopbaankamer.nl,
ospl.nl, ospl.de, printcontrol.nl, dankers-schilderwerken.nl, promonta.nl,
interim-denbosch.nl
relayhost =
sample_directory = /opt/csw/share/doc/postfix/samples
sendmail_path = /opt/csw/sbin/sendmail
smtp_bind_address = 213.207.90.2
smtp_helo_timeout = 60s
smtp_send_xforward_command = yes
smtp_skip_quit_response = yes
smtp_tls_session_cache_database = btree:${data_directory}/smtp_scache
smtpd_banner = $myhostname ESMTP
smtpd_client_connection_count_limit = 10
smtpd_client_restrictions = reject_rbl_client dnsbl.njabl.org, permit
smtpd_data_restrictions = reject_unauth_pipelining
smtpd_delay_reject = yes
smtpd_hard_error_limit = 12
smtpd_helo_required = yes
smtpd_helo_restrictions = permit_mynetworks, warn_if_reject
reject_non_fqdn_hostname, reject_invalid_hostname,
permit
smtpd_recipient_limit = 100
smtpd_recipient_restrictions = permit_sasl_authenticated,
permit_mynetworks, reject_non_fqdn_recipient,
reject_non_fqdn_hostname, reject_non_fqdn_sender,
reject_unauth_destination, reject_unlisted_recipient,
reject_unknown_recipient_domain, reject_unverified_recipient,
reject_invalid_hostname, reject_rbl_client virbl.dnsbl.bit.nl,
check_policy_service inet:127.0.0.1:12525, check_policy_service
inet:127.0.0.1:10023, permit
smtpd_sasl_auth_enable = yes
smtpd_sasl_authenticated_header = yes
smtpd_sasl_local_domain = $myhostname
smtpd_sasl_path = private/auth
smtpd_sasl_security_options = noanonymous
smtpd_sasl_type = dovecot
smtpd_sender_restrictions = permit_mynetworks,
reject_unknown_sender_domain, permit
smtpd_soft_error_limit = 3
smtpd_tls_cert_file = /home/yghosting/ssl/secure-youngguns-nl.pem
smtpd_tls_key_file = /home/yghosting/ssl/secure-youngguns-nl.key
smtpd_tls_session_cache_database = btree:${data_directory}/smtpd_scache
smtpd_use_tls = yes
soft_bounce = no
tls_random_source = dev:/dev/urandom
transport_maps = hash:/opt/csw/etc/postfix/transport
unknown_local_recipient_reject_code = 550
unverified_recipient_reject_code = 550
virtual_alias_maps = hash:/opt/csw/etc/postfix/virtual
