My Postfix is set up with virtual domains. This allows people to send an email to *@mydomain.com and it'll be forwarded to my gmail account. Basically the end goal is to simply allow people to email anything@mydomain.com and it will be forwarded on to me, it saves me from having seperate mailboxes.
This has worked fine for the few days it's been setup until I woke up this morning to several thousand Chinese spam emails sent from my postfix. They use alias's such as cff@mydomain.com, efff@mydomain.com, brez@mydomain.com to SEND mail externally to completely unrelated email addresses. To clarify, this is third party spam email abuse using my server.
I immediately freaked out and went to find what the problem is. There is no new users in /etc/passwd, and in /etc/shadow, only mine, the FTP, and root (with disabled SSH) are able to login. So it seems it must be a Postix config error.
I seemed to have fixed by adding
smtpd_client_restrictions = permit_mynetworks, reject
smtpd_recipient_restrictions = permit_mynetworks, permit_sasl_authenticated
# Block clients that speak too early.
smtpd_data_restrictions = reject_unauth_pipelining
# Enforce mail volume quota via policy service callouts.
smtpd_end_of_data_restrictions = check_policy_service unix:private/policy
to my main.cf. The mail.log is still filling up with all these attempts but the mail no longer gets sent out. An example
Aug 9 09:35:12 myusername postfix/smtpd[32085]: NOQUEUE: reject: RCPT from unknown[183.147.82.118]: 554 5.7.1 <unknown[183.147.82.118]>: Client host rejected: Access denied; from=<eff@mydomain$
Aug 9 09:35:14 myusername postfix/smtpd[32085]: lost connection after DATA from unknown[183.147.82.118]
Aug 9 09:35:14 myusername postfix/smtpd[32085]: disconnect from unknown[183.147.82.118]
The problem now is that is now blocks legitimate emails when I try and send anything to any of my domains.
554 5.7.1 <mail-ob0-f172.google.com[209.85.214.172]>: Client host rejected: Access denied
What can I do to
A) Allow any emails sent do my virtual domains (anything i.e hello@mydomain.com) to be forwarded onto my Gmail account, but not allow spammers to somehow use my server to SEND spam mail onwards.
And optionally B) Stop having all these attempts possible in the first place and cluttering up my mail.log
Here is my main.cf
# See /usr/share/postfix/main.cf.dist for a commented, more complete version
# Debian specific: Specifying a file name will cause the first
# line of that file to be used as the name. The Debian default
# is /etc/mailname.
#myorigin = /etc/mailname
smtpd_banner = $myhostname ESMTP $mail_name (Ubuntu)
biff = no
# appending .domain is the MUA's job.
append_dot_mydomain = no
# Uncomment the next line to generate "delayed mail" warnings
#delay_warning_time = 4h
readme_directory = no
# TLS parameters
smtpd_tls_cert_file=/etc/ssl/certs/ssl-cert-snakeoil.pem
smtpd_tls_key_file=/etc/ssl/private/ssl-cert-snakeoil.key
smtpd_use_tls=yes
smtpd_tls_session_cache_database = btree:${data_directory}/smtpd_scache
smtp_tls_session_cache_database = btree:${data_directory}/smtp_scache
# See /usr/share/doc/postfix/TLS_README.gz in the postfix-doc package for
# information on enabling SSL in the smtp client.
smtpd_relay_restrictions = permit_mynetworks permit_sasl_authenticated defer_unauth_destination
myhostname = mydomain1.com
alias_maps = hash:/etc/aliases
alias_database = hash:/etc/aliases
virtual_alias_domains = mydomain1.com, mydomain2.me
virtual_alias_maps = hash:/etc/postfix/virtual
myorigin = /etc/mailname
#mydestination = localhost.241.214.119, localhost
mydestination = $myhostname,localhost.$mydomain, localhost, $mydomain
#relayhost = mail.mydomain1.com
mynetworks = 127.0.0.0/8 [::ffff:127.0.0.0]/104 [::1]/128
mailbox_command = procmail -a "$EXTENSION"
mailbox_size_limit = 0
recipient_delimiter = +
inet_protocols = ipv4
milter_protocol = 2
milter_default_action = accept
smtpd_milters = inet:localhost:12301
non_smtpd_milters = inet:localhost:12301
smtp_generic_maps = hash:/etc/postfix/generic
smtpd_client_restrictions = permit_mynetworks, reject
# Spam control: exclude local clients and authenticated clients
# from DNSBL lookups.
smtpd_recipient_restrictions = permit_mynetworks, permit_sasl_authenticated
# Block clients that speak too early.
smtpd_data_restrictions = reject_unauth_pipelining
# Enforce mail volume quota via policy service callouts.
smtpd_end_of_data_restrictions = check_policy_service unix:private/policy
and my master.cf
#
# Postfix master process configuration file. For details on the format
# of the file, see the master(5) manual page (command: "man 5 master" or
# on-line: http://www.postfix.org/master.5.html).
#
# Do not forget to execute "postfix reload" after editing this file.
#
# ==========================================================================
# service type private unpriv chroot wakeup maxproc command + args
# (yes) (yes) (yes) (never) (100)
# ==========================================================================
smtp inet n - - - - smtpd
#smtp inet n - - - 1 postscreen
#smtpd pass - - - - - smtpd
#dnsblog unix - - - - 0 dnsblog
#tlsproxy unix - - - - 0 tlsproxy
#submission inet n - - - - smtpd
# -o syslog_name=postfix/submission
# -o smtpd_tls_security_level=encrypt
# -o smtpd_sasl_auth_enable=yes
# -o smtpd_reject_unlisted_recipient=no
# -o smtpd_client_restrictions=$mua_client_restrictions
# -o smtpd_helo_restrictions=$mua_helo_restrictions
# -o smtpd_sender_restrictions=$mua_sender_restrictions
# -o smtpd_recipient_restrictions=
# -o smtpd_relay_restrictions=permit_sasl_authenticated,reject
# -o milter_macro_daemon_name=ORIGINATING
#smtps inet n - - - - smtpd
# -o syslog_name=postfix/smtps
# -o smtpd_tls_wrappermode=yes
# -o smtpd_sasl_auth_enable=yes
# -o smtpd_reject_unlisted_recipient=no
# -o smtpd_client_restrictions=$mua_client_restrictions
# -o smtpd_helo_restrictions=$mua_helo_restrictions
# -o smtpd_sender_restrictions=$mua_sender_restrictions
# -o smtpd_recipient_restrictions=
# -o smtpd_relay_restrictions=permit_sasl_authenticated,reject
# -o milter_macro_daemon_name=ORIGINATING
#628 inet n - - - - qmqpd
pickup unix n - - 60 1 pickup
cleanup unix n - - - 0 cleanup
qmgr unix n - n 300 1 qmgr
#qmgr unix n - n 300 1 oqmgr
tlsmgr unix - - - 1000? 1 tlsmgr
rewrite unix - - - - - trivial-rewrite
bounce unix - - - - 0 bounce
defer unix - - - - 0 bounce
trace unix - - - - 0 bounce
verify unix - - - - 1 verify
flush unix n - - 1000? 0 flush
proxymap unix - - n - - proxymap
proxywrite unix - - n - 1 proxymap
smtp unix - - - - - smtp
relay unix - - - - - smtp
# -o smtp_helo_timeout=5 -o smtp_connect_timeout=5
showq unix n - - - - showq
error unix - - - - - error
retry unix - - - - - error
discard unix - - - - - discard
local unix - n n - - local
virtual unix - n n - - virtual
lmtp unix - - - - - lmtp
anvil unix - - - - 1 anvil
scache unix - - - - 1 scache
#
# ====================================================================
# Interfaces to non-Postfix software. Be sure to examine the manual
# pages of the non-Postfix software to find out what options it wants.
#
# Many of the following services use the Postfix pipe(8) delivery
# agent. See the pipe(8) man page for information about ${recipient}
# and other message envelope options.
# ====================================================================
#
# maildrop. See the Postfix MAILDROP_README file for details.
# Also specify in main.cf: maildrop_destination_recipient_limit=1
#
maildrop unix - n n - - pipe
flags=DRhu user=vmail argv=/usr/bin/maildrop -d ${recipient}
#
# ====================================================================
#
# Recent Cyrus versions can use the existing "lmtp" master.cf entry.
#
# Specify in cyrus.conf:
# lmtp cmd="lmtpd -a" listen="localhost:lmtp" proto=tcp4
#
# Specify in main.cf one or more of the following:
# mailbox_transport = lmtp:inet:localhost
# virtual_transport = lmtp:inet:localhost
#
# ====================================================================
#
# Cyrus 2.1.5 (Amos Gouaux)
# Also specify in main.cf: cyrus_destination_recipient_limit=1
#
#cyrus unix - n n - - pipe
# user=cyrus argv=/cyrus/bin/deliver -e -r ${sender} -m ${extension} ${user}
#
# ====================================================================
# Old example of delivery via Cyrus.
#
#old-cyrus unix - n n - - pipe
# flags=R user=cyrus argv=/cyrus/bin/deliver -e -m ${extension} ${user}
#
# ====================================================================
#
# See the Postfix UUCP_README file for configuration details.
#
uucp unix - n n - - pipe
flags=Fqhu user=uucp argv=uux -r -n -z -a$sender - $nexthop!rmail ($recipient)
#
# Other external delivery methods.
#
ifmail unix - n n - - pipe
flags=F user=ftn argv=/usr/lib/ifmail/ifmail -r $nexthop ($recipient)
bsmtp unix - n n - - pipe
flags=Fq. user=bsmtp argv=/usr/lib/bsmtp/bsmtp -t$nexthop -f$sender $recipient
scalemail-backend unix - n n - 2 pipe
flags=R user=scalemail argv=/usr/lib/scalemail/bin/scalemail-store ${nexthop} ${user} ${extension}
mailman unix - n n - - pipe
flags=FR user=list argv=/usr/lib/mailman/bin/postfix-to-mailman.py
${nexthop} ${user}
Any insight is appreciated!
