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Here is my problem:

My email address is for example something1@domain.com.

Everything is ok when Postfix receives email for address something1@domain.com.

But spammers often use random mailboxes, for example something5644343@domain.com. Postfix first checks email in Amavis spam-filter. After that checks database if mailbox exists. My server is overloaded when spammer send too much emails. I want to reject all emails for non exists mailboxes without spam check.

I tried "after-queue content filter" - http://www.postfix.org/FILTER_README.html - but without success.

My configuration:

/etc/postfix/main.cf:

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

virtual_alias_domains = proxy:mysql:/etc/postfix/mysql-virtual_alias_domains.cf

virtual_alias_maps =
    proxy:mysql:/etc/postfix/mysql-virtual_forwardings.cf,
   proxy:mysql:/etc/postfix/mysql-virtual_email2email.cf
virtual_transport = lmtp:unix:private/dovecot-lmtp
virtual_mailbox_maps = proxy:mysql:/etc/postfix/mysql-virtual_mailboxes.cf, proxy:mysql:/etc/postfix/mysql-virtual_forwardings.cf

virtual_mailbox_limit_maps = 4096M

proxy_read_maps = $local_recipient_maps $mydestination $virtual_alias_maps $virtual_alias_domains $virtual_mailbox_maps $virtual_mailbox_domains $relay_recipient_maps $relay_domains $canonical_maps $sender_canonical_maps $recipient_canonical_maps $relocated_maps $transport_maps $mynetworks $virtual_mailbox_limit_maps


smtpd_helo_restrictions = permit_mynetworks, permit_sasl_authenticated, reject_non_fqdn_helo_hostname, reject_unknown_helo_hostname

smtpd_helo_required = yes

smtpd_client_restrictions = permit_mynetworks, permit_sasl_authenticated, defer_unauth_destination
smtpd_sender_restrictions = permit_mynetworks, permit_sasl_authenticated, check_sender_access hash:/etc/postfix/sender_access, regexp:/etc/postfix/sender_access, reject_unknown_sender_domain, reject_non_fqdn_sender, reject_unknown_sender_domain, reject_unknown_reverse_client_hostname, reject_unknown_client_hostname, reject_unknown_sender_domain
smtpd_recipient_restrictions = permit_mynetworks,
                permit_sasl_authenticated,
                check_recipient_access hash:/etc/postfix/recipient_access,
                reject_invalid_hostname,
                reject_non_fqdn_sender,
                               reject_unknown_sender_domain,
                               reject_unknown_recipient_domain,
                               reject_unlisted_recipient,
                               reject_unauth_destination,
                               reject_unauth_pipelining,
                reject_non_fqdn_recipient

milter_default_action = accept
milter_protocol = 6
smtpd_milters = unix:var/run/opendkim/opendkim.sock
non_smtpd_milters = unix:var/run/opendkim/opendkim.sock

myorigin = localhost 

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

append_dot_mydomain = no

delay_warning_time = 4h

readme_directory = /usr/share/doc/postfix
html_directory = /usr/share/doc/postfix/html

compatibility_level = 2

smtpd_tls_cert_file=/var/www/_ssl/...pem
smtpd_tls_key_file=/var/www/_ssl/...pem
smtpd_use_tls=yes
smtpd_tls_session_cache_database = btree:${data_directory}/smtpd_scache
smtp_tls_session_cache_database = btree:${data_directory}/smtp_scache

smtpd_relay_restrictions = permit_mynetworks permit_sasl_authenticated defer_unauth_destination
myhostname = domain.com
mydomain = domain.com

mydestination = localhost
mynetworks = 127.0.0.0/8 127.0.0.1 [::ffff:127.0.0.0]/104 [::1]/128
mailbox_size_limit = 0
recipient_delimiter = +
inet_interfaces = all
inet_protocols = all

smtpd_sasl_auth_enable = yes
smtp_sasl_mechanism_filter = plain, login
smtp_sasl_security_options = noanonymous

smtpd_sasl_type = dovecot
smtpd_sasl_path = private/auth
smtpd_sasl_auth_enable = yes
smtpd_sasl_authenticated_header = yes
broken_sasl_auth_clients = no
queue_directory = /var/spool/postfix
smtpd_tls_security_level=may
transport_maps = proxy:mysql:/etc/postfix/mysql-virtual_transports.cf
local_recipient_maps = proxy:mysql:/etc/postfix/mysql-virtual_forwardings.cf

debug_peer_level = 10

virtual_uid_maps = static:5000
virtual_gid_maps = static:5000
message_size_limit = 104857600
smtputf8_enable = no

/etc/postfix/master.cf:

smtp      inet  n       -       n       -       -       smtpd
    -o content_filter=amavis:[127.0.0.1]:10024
submission inet n       -       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=permit_sasl_authenticated,reject
  -o milter_macro_daemon_name=ORIGINATING
smtps     inet  n       -       y       -       -       smtpd
  -o syslog_name=postfix/smtps
  -o smtpd_tls_wrappermode=yes
  -o smtpd_sasl_auth_enable=yes
  -o smtpd_reject_unlisted_recipient=no
  -o milter_macro_daemon_name=ORIGINATING
pickup    unix  n       -       y       60      1       pickup
cleanup   unix  n       -       y       -       0       cleanup
qmgr      unix  n       -       n       300     1       qmgr
tlsmgr    unix  -       -       y       1000?   1       tlsmgr
rewrite   unix  -       -       y       -       -       trivial-rewrite
bounce    unix  -       -       y       -       0       bounce
defer     unix  -       -       y       -       0       bounce
trace     unix  -       -       y       -       0       bounce
verify    unix  -       -       y       -       1       verify
flush     unix  n       -       y       1000?   0       flush
proxymap  unix  -       -       n       -       -       proxymap
proxywrite unix -       -       n       -       1       proxymap
smtp      unix  -       -       n       -       -       smtp
relay     unix  -       -       y       -       -       smtp
showq     unix  n       -       y       -       -       showq
error     unix  -       -       y       -       -       error
retry     unix  -       -       y       -       -       error
discard   unix  -       -       y       -       -       discard
local     unix  -       n       n       -       -       local
virtual   unix  -       n       n       -       -       virtual
lmtp      unix  -       -       y       -       -       lmtp
anvil     unix  -       -       y       -       1       anvil
scache    unix  -       -       y       -       1       scache
dovecot   unix  -       n       n       -       -       pipe
  flags=DRhu user=vmail:vmail argv=/usr/lib/dovecot/deliver -f ${sender} -d ${user}@${nexthop}
spamassassin unix -     n       n       -       -       pipe
    user=debian-spamd argv=/usr/bin/spamc -f -e
    /usr/sbin/sendmail -oi -f ${sender} ${recipient}
amavis    unix  -       -       y       -       20       smtp
    -o smtp_data_done_timeout=1200
    -o smtp_send_xforward_command=yes
    -o disable_dns_lookups=yes
    -o max_use=20
127.0.0.1:10025 inet n  -       -       -       -       smtpd
    -o content_filter=
    -o local_recipient_maps=
    -o relay_recipient_maps=
    -o smtpd_restriction_classes=
    -o smtpd_delay_reject=no
    -o smtpd_client_restrictions=permit_mynetworks,reject
    -o smtpd_helo_restrictions=
    -o smtpd_sender_restrictions=
    -o smtpd_recipient_restrictions=permit_mynetworks,reject
    -o smtpd_data_restrictions=reject_unauth_pipelining
    -o smtpd_end_of_data_restrictions=
    -o mynetworks=127.0.0.0/8
    -o smtpd_error_sleep_time=0
    -o smtpd_soft_error_limit=1001
    -o smtpd_hard_error_limit=1000
    -o smtpd_client_connection_count_limit=0
    -o smtpd_client_connection_rate_limit=0

maildrop  unix  -       n       n       -       -       pipe
  flags=DRhu user=vmail argv=/usr/bin/maildrop -d ${recipient}

uucp      unix  -       n       n       -       -       pipe
  flags=Fqhu user=uucp argv=uux -r -n -z -a$sender - $nexthop!rmail ($recipient)

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}

policyd-spf  unix  -       n       n       -       0       spawn
    user=policyd-spf argv=/usr/bin/policyd-spf

Does anyone know?

djlj
  • 1
  • 2

1 Answers1

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Problem solved.

You must edit you SQL query if you've got a same problem like me.

Existing email address: something1@domain.com

I used this query in /etc/postfix/mysql-virtual_mailboxes.cf:

SELECT IF(u.username!='', CONCAT('/var/mail/', u.domain, '/', u.username), f.destination) FROM forwardings f INNER JOIN users u ON CONCAT(u.username, '@', u.domain)=f.destination WHERE f.source='%s' OR SUBSTRING_INDEX(f.source, '@', -1)= '%d' LIMIT 1

Example: email is for something5644343@domain.com. MySQL query checks only domain (%d). Domain exists. So everything is ok Postfix thinks.

But you can edit this query like this:

SELECT CONCAT('/var/mail/', u.username, '/', u.domain) FROM forwardings f INNER JOIN users u ON CONCAT(u.username, '@', u.domain)=f.destination WHERE f.source='%s' OR f.source='@%d' UNION ALL SELECT CONCAT('/var/mail/', domain, '/', username) FROM users WHERE CONCAT(username, '@', domain)='%s' LIMIT 1

Voilà ! Email for something1@domain.com is ok. Email for something5644343@domain.com is not ok => Recipient address rejected: User unknown in virtual mailbox table.

djlj
  • 1
  • 2