Боремся со спамом стандартными средствами почтовика (на примере Exim)

acl_whitelist:

  accept  condition = ${lookup mysql{SQL_WHOST_QUERY}{yes}{no}}
  accept  hosts   = ${if exists{CONFDIR/local_host_whitelist}{CONFDIR/local_host_whitelist}{}}
  deny

acl_is_work_time:       # Рабочее время  08:00 - 19:00  = 03:00 - 14:00 (02 << 15)

  accept  condition = ${if and { {>{$acl_c2}{2}} {<{$acl_c2}{15}} } {yes}{no}}
  deny

acl_check_connect:

  warn    set acl_c0  = ${eval:0}
  warn    set acl_c3  = ${eval:0}

  deny    message = Empty HELO is not allowed ERR_MES_ADD
    condition = ${if eq{$sender_helo_name}{}{yes}{no}}

  deny    message = Your IP in HELO is not allowed
    condition = ${if eq{$sender_helo_name}{$sender_host_address}{yes}{no}}

  deny    message = Our IP in HELO is not allowed
    condition = ${if eq{$sender_helo_name}{OUR_IP1}{yes}{no}}

  deny    message = Our IP in HELO is not allowed
    condition = ${if eq{$sender_helo_name}{OUR_IP2}{yes}{no}}

  deny    message = Localhost in HELO is not allowed ERR_MES_ADD
    condition = ${if eq{$sender_helo_name}{localhost}{yes}{no}}

  deny   message = 127.0.0.1 in HELO is not allowed
   condition = ${if eq{$sender_helo_name}{127.0.0.1}{yes}{no}}

  deny   message = Host name in HELO must contents letters
   !acl    = acl_whitelist
   condition = ${if match{$sender_helo_name}{\N^\d+$\N}{yes}{no}}

  defer   message = 4 numbers in HELO is not allowed ERR_MES_ADD
    !acl    = acl_whitelist
    condition = ${if match{$sender_helo_name}{\N(\d{1,3}[-\.]){3}\d{1,3}\N}{yes}{no}}
    delay   = 10s

  defer   message = Text in HELO ($sender_helo_name) must be hostname ERR_MES_ADD
    !acl    = acl_whitelist
    !condition  = ${if match{$sender_helo_name}{\N^([a-zA-Z\d][-a-zA-Z\d_]{0,19}\.){1,5}[a-zA-Z]{2,5}$\N}{yes}{no}}
    delay   = 10s

  defer   message = Hostname in HELO is not allowed ERR_MES_ADD
    !acl    = acl_whitelist
    condition = ${if match{$sender_helo_name} \
        {home|dialup|dialin|ppp|dsl|pool|peer|dhcp|dynamic|transcapbank}{yes}{no}}
    delay   = 10s

  warn    set acl_m1  = ${lookup dnsdb{defer_never,a=$sender_helo_name}}

  defer   message = Hostname in HELO does not resolve ERR_MES_ADD
    !acl    = acl_whitelist
    condition = ${if eq{$acl_m1}{}{yes}{no}}
    delay   = 10s

acl_check_rcpt:

   ...

  defer   message = Bad reverse DNS ERR_MES_ADD
    !acl    = acl_whitelist
    condition = ${if eq{$sender_host_name}{}{yes}{no}}
    !acl    = acl_is_work_time

  defer   message = Bad helo hostname ERR_MES_ADD
    !acl    = acl_whitelist
    !verify = helo
    !acl    = acl_is_work_time

  defer   message = Limit for bad reverse DNS ERR_MES_ADD
    !acl    = acl_whitelist
    condition = ${if eq{$sender_host_name}{}{yes}{no}}
    set acl_c5  = 2
    delay   = 35s
    ratelimit = 1 / 2h / strict / $sender_host_address
    set acl_m0  = ${lookup mysql{SQL_INS_BHOST}{}}

  defer   message = Limit for bad helo hostname ERR_MES_ADD
    !acl    = acl_whitelist
    !verify = helo
    set acl_c5  = 3
    delay   = 35s
    ratelimit = 1 / 2h / strict / $sender_host_address
    set acl_m0  = ${lookup mysql{SQL_INS_BHOST}{}}

  deny    message = Your IP in blacklist $dnslist_domain ($dnslist_text) ERR_MES_ADD
    !acl    = acl_whitelist
    log_message = Sender IP in $dnslist_domain ($dnslist_text)
    dnslists  = bl.spamcop.net : dul.ru : dnsbl.sorbs.net
#   dnslists  = dnsbl.njabl.org : relays.ordb.org : list.dsbl.org : bl.spamcop.net : dul.ru
#     dynablock.njabl.org : xbl-sbl.spamhaus.org : dnsbl.net.au
#     xbl.spamhaus.org : cbl.abuseat.org

  deny    message = Sender verification failed ERR_MES_ADD
    domains       = +local_domains
    !acl    = acl_whitelist
    !verify       = sender/callout=30s,defer_ok


acl_check_mime:

  warn    decode  = default

  deny    message = File type is not allowed ($mime_filename)
    condition = ${if match {${lc:$mime_filename}} \
      {\N(\.exe|\.pif|\.bat|\.cmd|\.scr|\.lnk|\.com|\.vbs|\.cpl|\.sql)$\N} {1}{0}}

  deny    message = Chinese text is not allowed ERR_MES_ADD
    condition = ${if eq{$mime_charset}{gb2312}{1}{0}}

  accept