1 (edited by ensysit 2021-05-15 18:40:51)

Topic: DNSBL not working - Can see blacklisted IP's (ex: 91.191.209.165) pass

==== REQUIRED BASIC INFO OF YOUR IREDMAIL SERVER ====
- iRedMail version (check /etc/iredmail-release): 1.4.0 - IredMail Pro
- Deployed with iRedMail Easy or the downloadable installer? Downloadable Installer
- Linux/BSD distribution name and version: CentOS 7.8
- Store mail accounts in which backend (LDAP/MySQL/PGSQL):  MariaDB
- Web server (Apache or Nginx): NGINX
- Manage mail accounts with iRedAdmin-Pro? Yes
- [IMPORTANT] Related original log or error message is required if you're experiencing an issue.
====

Hello iRedMail / Postfix gurus. I am having an issue where I see thousands of requests from currently blacklisted IPs via DNS BL (Spamhaus ZEN shows 91.191.209.165 as listed) enter in Postfix and simply get rejected because the "mailbox does not exist" instead of immediately being rejected because they are blacklisted via DNSBL with Postscreen. My maillog is filled with tens of thousands of entries like this (I renamed my domain to mydomain.com for privacy reasons). My postfix main.cf is completely shown below, shouldn't it filter the IP as it is on the DNSBL as it is configured in the Postscreen section ? Why is in not ? Please help

---- Maillog excerpt of offending messages from DNSBL Blacklisted IP ---

131:May  9 04:09:31 mail postfix/smtpd[13393]: NOQUEUE: reject: RCPT from unknown[91.191.209.165]: 550 5.1.1 <holiday@mydomain.com>: Recipient address rejected: User unknown in virtual mailbox table; from=<hid7gb8zppe7s6@grup
pocaravati.it> to=<holiday@mydomain.com> proto=ESMTP helo=<[91.191.209.130]>
132:May  9 04:09:31 mail postfix/smtpd[13393]: NOQUEUE: reject: RCPT from unknown[91.191.209.165]: 550 5.1.1 <sad@mydomain.com>: Recipient address rejected: User unknown in virtual mailbox table; from=<hid7gb8zppe7s6@gruppoca
ravati.it> to=<sad@mydomain.com> proto=ESMTP helo=<[91.191.209.130]>
133:May  9 04:09:31 mail postfix/smtpd[13393]: NOQUEUE: reject: RCPT from unknown[91.191.209.165]: 550 5.1.1 <kind@mydomain.com>: Recipient address rejected: User unknown in virtual mailbox table; from=<hid7gb8zppe7s6@gruppoc
aravati.it> to=<kind@mydomain.com> proto=ESMTP helo=<[91.191.209.130]>
134:May  9 04:09:31 mail postfix/smtpd[13393]: NOQUEUE: reject: RCPT from unknown[91.191.209.165]: 550 5.1.1 <dominate@mydomain.com>: Recipient address rejected: User unknown in virtual mailbox table; from=<hid7gb8zppe7s6@gru
ppocaravati.it> to=<dominate@mydomain.com> proto=ESMTP helo=<[91.191.209.130]>
135:May  9 04:09:31 mail postfix/smtpd[13393]: NOQUEUE: reject: RCPT from unknown[91.191.209.165]: 550 5.1.1 <debate@mydomain.com>: Recipient address rejected: User unknown in virtual mailbox table; from=<hid7gb8zppe7s6@grupp
ocaravati.it> to=<debate@mydomain.com> proto=ESMTP helo=<[91.191.209.130]>
136:May  9 04:09:31 mail postfix/smtpd[13393]: NOQUEUE: reject: RCPT from unknown[91.191.209.165]: 550 5.1.1 <novel@mydomain.com>: Recipient address rejected: User unknown in virtual mailbox table; from=<hid7gb8zppe7s6@gruppo
caravati.it> to=<novel@mydomain.com> proto=ESMTP helo=<[91.191.209.130]>
137:May  9 04:09:31 mail postfix/smtpd[13393]: NOQUEUE: reject: RCPT from unknown[91.191.209.165]: 550 5.1.1 <regime@mydomain.com>: Recipient address rejected: User unknown in virtual mailbox table; from=<hid7gb8zppe7s6@grupp
ocaravati.it> to=<regime@mydomain.com> proto=ESMTP helo=<[91.191.209.130]>
138:May  9 04:09:31 mail postfix/smtpd[13393]: NOQUEUE: reject: RCPT from unknown[91.191.209.165]: 550 5.1.1 <exciting@mydomain.com>: Recipient address rejected: User unknown in virtual mailbox table; from=<hid7gb8zppe7s6@gru
ppocaravati.it> to=<exciting@mydomain.com> proto=ESMTP helo=<[91.191.209.130]>
139:May  9 04:09:31 mail postfix/smtpd[13393]: NOQUEUE: reject: RCPT from unknown[91.191.209.165]: 550 5.1.1 <wife@mydomain.com>: Recipient address rejected: User unknown in virtual mailbox table; from=<hid7gb8zppe7s6@gruppoc
aravati.it> to=<wife@mydomain.com> proto=ESMTP helo=<[91.191.209.130]>
140:May  9 04:09:31 mail postfix/smtpd[13393]: NOQUEUE: reject: RCPT from unknown[91.191.209.165]: 550 5.1.1 <smoke@mydomain.com>: Recipient address rejected: User unknown in virtual mailbox table; from=<hid7gb8zppe7s6@gruppo
caravati.it> to=<smoke@mydomain.com> proto=ESMTP helo=<[91.191.209.130]>
141:May  9 04:09:31 mail postfix/smtpd[13393]: NOQUEUE: reject: RCPT from unknown[91.191.209.165]: 550 5.1.1 <education@mydomain.com>: Recipient address rejected: User unknown in virtual mailbox table; from=<hid7gb8zppe7s6@gr
uppocaravati.it> to=<education@mydomain.com> proto=ESMTP helo=<[91.191.209.130]>


-------- Full Postfix content of main.cf (I changed my domain to mydomain.com in this post) --------

# --------------------
# INSTALL-TIME CONFIGURATION INFORMATION
#
# location of the Postfix queue. Default is /var/spool/postfix.
queue_directory = /var/spool/postfix

# location of all postXXX commands. Default is /usr/sbin.
command_directory = /usr/sbin

# location of all Postfix daemon programs (i.e. programs listed in the
# master.cf file). This directory must be owned by root.
# Default is /usr/libexec/postfix
daemon_directory = /usr/libexec/postfix

# location of Postfix-writable data files (caches, random numbers).
# This directory must be owned by the mail_owner account (see below).
# Default is /var/lib/postfix.
data_directory = /var/lib/postfix

# owner of the Postfix queue and of most Postfix daemon processes.
# Specify the name of a user account THAT DOES NOT SHARE ITS USER OR GROUP ID
# WITH OTHER ACCOUNTS AND THAT OWNS NO OTHER FILES OR PROCESSES ON THE SYSTEM.
# In particular, don't specify nobody or daemon. PLEASE USE A DEDICATED USER.
# Default is postfix.
mail_owner = postfix

# The following parameters are used when installing a new Postfix version.
#
# sendmail_path: The full pathname of the Postfix sendmail command.
# This is the Sendmail-compatible mail posting interface.
#
sendmail_path = /usr/sbin/sendmail.postfix

# newaliases_path: The full pathname of the Postfix newaliases command.
# This is the Sendmail-compatible command to build alias databases.
#
newaliases_path = /usr/bin/newaliases.postfix

# full pathname of the Postfix mailq command.  This is the Sendmail-compatible
# mail queue listing command.
mailq_path = /usr/bin/mailq.postfix

# group for mail submission and queue management commands.
# This must be a group name with a numerical group ID that is not shared with
# other accounts, not even with the Postfix account.
setgid_group = postdrop

# external command that is executed when a Postfix daemon program is run with
# the -D option.
#
# Use "command .. & sleep 5" so that the debugger can attach before
# the process marches on. If you use an X-based debugger, be sure to
# set up your XAUTHORITY environment variable before starting Postfix.
#
debugger_command =
    PATH=/bin:/usr/bin:/usr/local/bin:/usr/X11R6/bin
    ddd $daemon_directory/$process_name $process_id & sleep 5

debug_peer_level = 2

# --------------------
# CUSTOM SETTINGS
#

# SMTP server response code when recipient or domain not found.
unknown_local_recipient_reject_code = 550

# Do not notify local user.
biff = no

# Disable the rewriting of "site!user" into "user@site".
swap_bangpath = no

# Disable the rewriting of the form "user%domain" to "user@domain".
allow_percent_hack = no

# Allow recipient address start with '-'.
allow_min_user = no

# Disable the SMTP VRFY command. This stops some techniques used to
# harvest email addresses.
disable_vrfy_command = yes

# Enable both IPv4 and/or IPv6: ipv4, ipv6, all.
inet_protocols = all

# Enable all network interfaces.
inet_interfaces = all

#
# TLS settings.
#
# SSL key, certificate, CA
#
smtpd_tls_key_file = /etc/pki/tls/private/iRedMail.key
smtpd_tls_cert_file = /etc/pki/tls/certs/iRedMail.crt
smtpd_tls_CAfile = /etc/pki/tls/certs/iRedMail.crt

#
# Disable SSLv2, SSLv3
#
smtpd_tls_protocols = !SSLv2 !SSLv3
smtpd_tls_mandatory_protocols = !SSLv2 !SSLv3
smtp_tls_protocols = !SSLv2 !SSLv3
smtp_tls_mandatory_protocols = !SSLv2 !SSLv3
lmtp_tls_protocols = !SSLv2 !SSLv3
lmtp_tls_mandatory_protocols = !SSLv2 !SSLv3

#
# Fix 'The Logjam Attack'.
#
smtpd_tls_exclude_ciphers = aNULL, eNULL, EXPORT, DES, RC4, MD5, PSK, aECDH, EDH-DSS-DES-CBC3-SHA, EDH-RSA-DES-CDC3-SHA, KRB5-DE5, CBC3-SHA
smtpd_tls_dh512_param_file = /etc/pki/tls/dh512_param.pem
smtpd_tls_dh1024_param_file = /etc/pki/tls/dh2048_param.pem

tls_random_source = dev:/dev/urandom

# Log only a summary message on TLS handshake completion — no logging of client
# certificate trust-chain verification errors if client certificate
# verification is not required. With Postfix 2.8 and earlier, log the summary
# message, peer certificate summary information and unconditionally log
# trust-chain verification errors.
smtp_tls_loglevel = 1
smtpd_tls_loglevel = 1

# Opportunistic TLS: announce STARTTLS support to remote SMTP clients, but do
# not require that clients use TLS encryption.
smtpd_tls_security_level = may

# Produce `Received:` message headers that include information about the
# protocol and cipher used, as well as the remote SMTP client CommonName and
# client certificate issuer CommonName.
# This is disabled by default, as the information may be modified in transit
# through other mail servers. Only information that was recorded by the final
# destination can be trusted.
#smtpd_tls_received_header = yes

# Opportunistic TLS, used when Postfix sends email to remote SMTP server.
# Use TLS if this is supported by the remote SMTP server, otherwise use
# plaintext.
# References:
#   - http://www.postfix.org/TLS_README.html#client_tls_may
#   - http://www.postfix.org/postconf.5.html# … rity_level
smtp_tls_security_level = may

# Use the same CA file as smtpd.
smtp_tls_CAfile = $smtpd_tls_CAfile
smtp_tls_note_starttls_offer = yes

# Enable long, non-repeating, queue IDs (queue file names).
# The benefit of non-repeating names is simpler logfile analysis and easier
# queue migration (there is no need to run "postsuper" to change queue file
# names that don't match their message file inode number).
#enable_long_queue_ids = yes

# Reject unlisted sender and recipient
smtpd_reject_unlisted_recipient = yes
smtpd_reject_unlisted_sender = yes

# Header and body checks with PCRE table
header_checks = pcre:/etc/postfix/header_checks
body_checks = pcre:/etc/postfix/body_checks.pcre

# A mechanism to transform commands from remote SMTP clients.
# This is a last-resort tool to work around client commands that break
# interoperability with the Postfix SMTP server. Other uses involve fault
# injection to test Postfix's handling of invalid commands.
# Requires Postfix-2.7+.
#smtpd_command_filter = pcre:/etc/postfix/command_filter.pcre

# HELO restriction
smtpd_helo_required = yes
smtpd_helo_restrictions =
    permit_mynetworks
    permit_sasl_authenticated
    check_helo_access pcre:/etc/postfix/helo_access.pcre
    reject_non_fqdn_helo_hostname
    reject_unknown_helo_hostname

# Sender restrictions
smtpd_sender_restrictions =
    reject_non_fqdn_sender
    reject_unlisted_sender
    permit_mynetworks
    permit_sasl_authenticated
    check_sender_access pcre:/etc/postfix/sender_access.pcre
    reject_unknown_sender_domain

# Recipient restrictions
smtpd_recipient_restrictions =
    reject_unknown_recipient_domain
    reject_non_fqdn_recipient
    reject_unlisted_recipient
    check_policy_service inet:127.0.0.1:7777
    permit_mynetworks
    permit_sasl_authenticated
    reject_unauth_destination
    check_policy_service inet:127.0.0.1:12340

# END-OF-MESSAGE restrictions
smtpd_end_of_data_restrictions =
    check_policy_service inet:127.0.0.1:7777

# Data restrictions
smtpd_data_restrictions = reject_unauth_pipelining

proxy_read_maps = $canonical_maps $lmtp_generic_maps $local_recipient_maps $mydestination $mynetworks $recipient_bcc_maps $recipient_canonical_maps $relay_domains $relay_recipient_maps $relocated_maps $sender_bcc_maps $sender_canonical_maps $smtp_generic_maps $smtpd_sender_login_maps $transport_maps $virtual_alias_domains $virtual_alias_maps $virtual_mailbox_domains $virtual_mailbox_maps $smtpd_sender_restrictions $sender_dependent_relayhost_maps

# Avoid duplicate recipient messages. Default is 'yes'.
enable_original_recipient = no

# Virtual support.
virtual_minimum_uid = 2000
virtual_uid_maps = static:2000
virtual_gid_maps = static:2000
virtual_mailbox_base = /var/vmail

# Do not set virtual_alias_domains.
virtual_alias_domains =

#
# Enable SASL authentication on port 25 and force TLS-encrypted SASL authentication.
# WARNING: NOT RECOMMENDED to enable smtp auth on port 25, all end users should
#          be forced to submit email through port 587 instead.
#
#smtpd_sasl_auth_enable = yes
#smtpd_sasl_security_options = noanonymous
#smtpd_tls_auth_only = yes

# hostname
myhostname = mail.mydomain.com
myorigin = mail.mydomain.com
mydomain = mail.mydomain.com

# trusted SMTP clients which are allowed to relay mail through Postfix.
#
# Note: additional IP addresses/networks listed in mynetworks should be listed
#       in iRedAPD setting 'MYNETWORKS' (in `/opt/iredapd/settings.py`) too.
#       for example:
#
#       MYNETWORKS = ['xx.xx.xx.xx', 'xx.xx.xx.0/24', ...]
#
mynetworks = 127.0.0.1, 80.82.77.165 [::1]

# Accepted local emails
mydestination = $myhostname, localhost, localhost.localdomain

alias_maps = hash:/etc/postfix/aliases
alias_database = hash:/etc/postfix/aliases

# Default message_size_limit.
# changed from 26214400 by XXX on Jan 5 2021
message_size_limit = 26214400
#message_size_limit = 900000000


# The set of characters that can separate a user name from its extension
# (example: user+foo), or a .forward file name from its extension (example:
# .forward+foo).
# Postfix 2.11 and later supports multiple characters.
recipient_delimiter = +

# The time after which the sender receives a copy of the message headers of
# mail that is still queued. Default setting is disabled (0h) by Postfix.
#delay_warning_time = 1h
#
# Lookup virtual mail accounts
#
transport_maps =
    proxy:mysql:/etc/postfix/mysql/transport_maps_user.cf
    proxy:mysql:/etc/postfix/mysql/transport_maps_maillist.cf
    proxy:mysql:/etc/postfix/mysql/transport_maps_domain.cf

sender_dependent_relayhost_maps =
    proxy:mysql:/etc/postfix/mysql/sender_dependent_relayhost_maps.cf

# Lookup table with the SASL login names that own the sender (MAIL FROM) addresses.
smtpd_sender_login_maps =
    proxy:mysql:/etc/postfix/mysql/sender_login_maps.cf

virtual_mailbox_domains =
    proxy:mysql:/etc/postfix/mysql/virtual_mailbox_domains.cf

relay_domains =
    $mydestination
    proxy:mysql:/etc/postfix/mysql/relay_domains.cf

virtual_mailbox_maps =
    proxy:mysql:/etc/postfix/mysql/virtual_mailbox_maps.cf

virtual_alias_maps =
    proxy:mysql:/etc/postfix/mysql/virtual_alias_maps.cf
    proxy:mysql:/etc/postfix/mysql/domain_alias_maps.cf
    proxy:mysql:/etc/postfix/mysql/catchall_maps.cf
    proxy:mysql:/etc/postfix/mysql/domain_alias_catchall_maps.cf

sender_bcc_maps =
    proxy:mysql:/etc/postfix/mysql/sender_bcc_maps_user.cf
    proxy:mysql:/etc/postfix/mysql/sender_bcc_maps_domain.cf

recipient_bcc_maps =
    proxy:mysql:/etc/postfix/mysql/recipient_bcc_maps_user.cf
    proxy:mysql:/etc/postfix/mysql/recipient_bcc_maps_domain.cf

#
# Postscreen
#
postscreen_greet_action = enforce
postscreen_blacklist_action = enforce
postscreen_dnsbl_action = enforce
postscreen_dnsbl_threshold = 2
postscreen_dnsbl_sites =
    zen.spamhaus.org=127.0.0.[2..11]*3
    b.barracudacentral.org=127.0.0.2*2

postscreen_dnsbl_reply_map = texthash:/etc/postfix/postscreen_dnsbl_reply
postscreen_access_list = permit_mynetworks cidr:/etc/postfix/postscreen_access.cidr

# Require Postfix-2.11+
#postscreen_dnsbl_whitelist_threshold = -2
#
# Dovecot SASL support.
#
smtpd_sasl_type = dovecot
smtpd_sasl_path = private/dovecot-auth
virtual_transport = dovecot
dovecot_destination_recipient_limit = 1

#
# Amavisd + SpamAssassin + ClamAV
#
content_filter = smtp-amavis:[127.0.0.1]:10024

# Concurrency per recipient limit.
smtp-amavis_destination_recipient_limit = 1
mlmmj_destination_recipient_limit = 1
readme_directory = /usr/share/doc/postfix-2.10.1/README_FILES
sample_directory = /usr/share/doc/postfix-2.10.1/samples
html_directory = no
manpage_directory = /usr/share/man

2

Re: DNSBL not working - Can see blacklisted IP's (ex: 91.191.209.165) pass

Please show us full content of file /etc/postfix/master.cf. Is postscreen service enabled?

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