Hi all,
I am having a problem with a server getting listed on ips.backscatterer.org.
I have been researchng and reviewing the config shown below, but am not 'getting it'.
I want to allow bounces to local addresses only.
Also, I am not so sure I understand the verify / callback process vrs. the config below.
If anyone cares to review it and comment, I would be greatful.
-Grant
######################################################################
# MAIN CONFIGURATION SETTINGS #
######################################################################
primary_hostname = thishost.mydomain.com
domainlist local_domains = /etc/virtual/domains
domainlist filtered_domains = /etc/virtual/filtered_domains
hostlist filtering_hosts = /etc/virtual/filtering_hosts
domainlist relay_to_domains =
hostlist relay_from_hosts = /etc/virtual/domains
hostlist blacklisted_domains = /etc/virtual/blacklist
hostlist spf_bypass = /etc/virtual/spf_bypass
hostlist whitelist = /etc/virtual/whitelist
acl_smtp_rcpt = acl_check_rcpt
trusted_users = mailnull:root:webmail:www
exim_user = mailnull
exim_group = mail
never_users =
host_lookup = *
rfc1413_hosts = *
rfc1413_query_timeout = 5s
ignore_bounce_errors_after = 0s
timeout_frozen_after = 0s
auto_thaw = 6h
return_path_remove
untrusted_set_sender = *
helo_allow_chars = _
daemon_smtp_ports = 25 : 109 : 587
bounce_message_file = /usr/local/etc/exim/bounce_message_file
warn_message_file = /usr/local/etc/exim/warn_message_file
return_size_limit = 10000
bounce_return_message = false
delay_warning = 72h
smtp_accept_max = 100
smtp_accept_max_per_host = 10
smtp_return_error_details = yes
log_selector = +incoming_interface +deliver_time +delivery_size +received_sender \
+received_recipients +sender_on_delivery +subject +address_rewrite +all_parents
# log_selector = +all
#
# My Attempt at greylisting
#
hide mysql_servers = localhost/exim_db/exim/password:
GREYLIST_TEST = SELECT IF(NOW() > block_expires, 2, 1) \
FROM exim_greylist \
WHERE relay_ip = '${quote_mysql:$sender_host_address}' \
AND from_domain = '${quote_mysql:$sender_address_domain}' \
AND record_expires > NOW()
GREYLIST_ADD = INSERT INTO exim_greylist \
SET relay_ip = '${quote_mysql:$sender_host_address}', \
from_domain = '${quote_mysql:$sender_address_domain}', \
block_expires = DATE_ADD(NOW(), INTERVAL 1 MINUTE), \
record_expires = DATE_ADD(NOW(), INTERVAL 14 DAY), \
origin_type = 'AUTO', \
create_time = NOW()
GREYLIST_UPDATE = UPDATE exim_greylist \
SET record_expires = DATE_ADD(now(), INTERVAL 14 DAY) \
WHERE relay_ip = '${quote_mysql:$sender_host_address}' \
AND from_domain = '${quote_mysql:$sender_address_domain}' \
AND record_expires > NOW()
######################################################################
# ACL CONFIGURATION #
# Specifies access control lists for incoming SMTP mail #
######################################################################
begin acl
acl_check_rcpt:
accept hosts = :
deny local_parts = ^.*[@%!/|] : ^\\.
accept authenticated = *
endpass
accept hosts = +relay_from_hosts
endpass
############################################################################################
# Mail is being rejected on some hosts because the mail MX is only set to a mail filtering system
# and our server is rejecting it because some mail servers see the lesser priorty
# MX and try to oour server directly instead of going though the mail filtering system.
# UPDATE: All secondary MXs removed from DNS zones. Reenabled monday Oct 5 2009.
accept domains = +filtered_domains
hosts = +filtering_hosts
verify = recipient
deny message = Please use the public MX server for the domain $domain
domains = +filtered_domains
hosts = !+filtering_hosts
###########################################################################################
deny senders = :
condition = ${if > {$recipients_count}{2}{1}}
message = Bounces must have only a single recipient
log_message = BACKSCATTER - RECIPIENTS $recipients_count
deny message = rejected because $sender_host_address was \
found in our blacklist
hosts = +blacklisted_domains
log_message = BLACKLISTED DOMAIN FOUND IN $blacklisted_domains
deny
! condition = ${lookup dnsdb{defer_never,ptr=$sender_host_address}{yes}}
log_message = NO PTR [rDNS] FOUND FOR $sender_host_address
message = We do not accept mail from hosts with missing \
or incorrect rDNS.
deny senders = :
! hosts = +whitelist
dnslists = ips.backscatterer.org
message = This message looks like a bounce, and your server is listed at \
ips.backscatterer.org, so I assume that this is "backscatter". \
Please configure your mail server to not send "backscatter spam". \
For advice, try http://www.dontbouncespam.org/
log_message = BACKSCATTER - INCOMING
warn set acl_m2 = ${lookup mysql{GREYLIST_TEST}{$value}{0}}
defer ! hosts = +whitelist
! hosts = +relay_from_hosts
! authenticated = *
condition = ${if eq{$acl_m2}{0}{yes}}
condition = ${lookup mysql{GREYLIST_ADD}{yes}{no}}
message = Now greylisted - please try again in 1 minute.
log_message = ADDING TO GREYLIST
defer ! hosts = +whitelist
! hosts = +relay_from_hosts
! authenticated = *
condition = ${if eq{$acl_m2}{1}{yes}}
message = Still greylisted - please try again in 1 minute.
log_message = STILL GREYLISTED
defer
! hosts = +whitelist
! hosts = +relay_from_hosts
! authenticated = *
condition = ${lookup mysql{GREYLIST_UPDATE}{no}{no}}
message = Greylist update failed
log_message = GREYLIST UPDATE FAILED
require verify = sender
accept hosts = +spf_bypass
spf = fail
logwrite = SPF - REFLEXION $sender_host_address is OK for \
$sender_address_domain
deny message = SPF - INCOMING $sender_host_address \
is not allowed to send mail from $sender_address_domain
spf = fail
accept domains = +local_domains
endpass
message = unknown user
verify = recipient
accept domains = +relay_to_domains
endpass
message = unrouteable address
verify = recipient
######################################################################
# ROUTERS CONFIGURATION #
# Specifies how addresses are handled #
######################################################################
# THE ORDER IN WHICH THE ROUTERS ARE DEFINED IS IMPORTANT! #
# An address is passed to each router in turn until it is accepted. #
######################################################################
begin routers
dnslookup_ccio:
driver = dnslookup
domains = ! +local_domains
condition = ${if eq {$sender_address_domain}{ccio.on.ca}{Yes}{No}}
transport = remote_smtp_ccio
ignore_target_hosts = 0.0.0.0 : 127.0.0.0/8
no_more
dnslookup_owm:
driver = dnslookup
domains = ! +local_domains
condition = ${if eq {$sender_host_address}{127.0.0.1} {yes}{no}}
transport = remote_smtp_owm
ignore_target_hosts = 0.0.0.0 : 127.0.0.0/8
no_more
dnslookup_local:
driver = dnslookup
domains = ! +local_domains
condition = ${lookup {$sender_address_domain} lsearch {/etc/virtual/domains} {yes}{no}}
transport = remote_smtp_local
ignore_target_hosts = 0.0.0.0 : 127.0.0.0/8
no_more
dnslookup_bounce:
driver = dnslookup
domains = ! +local_domains
condition = ${if eq {$sender_address_local_part}{} {yes}{no}}
transport = remote_smtp_bounce
ignore_target_hosts = 0.0.0.0 : 127.0.0.0/8
no_more
dnslookup_alias:
driver = dnslookup
domains = ! +local_domains
transport = remote_smtp_alias
ignore_target_hosts = 0.0.0.0 : 127.0.0.0/8
no_more
spamcheck_router:
driver = accept
no_verify
condition = "${if and { {!def:h_X-Spam-Flag:} {!eq {$received_protocol}\
{spam-scanned}}} {1}{0}}"
transport = spamcheck
virtual_alias:
driver = redirect
allow_defer
allow_fail
data = ${lookup {$local_part} lsearch {/home/$domain/mail/aliases}}
domains = /etc/virtual/domains
require_files = /home/$domain/mail/aliases
condition = ${lookup {$local_part} lsearch {/home/$domain/mail/aliases} {yes}{no}}
qualify_preserve_domain
retry_use_local_part
check_ancestor
one_time
file_transport = address_file
pipe_transport = address_pipe
reply_transport = address_reply
autoreply_router:
driver = accept
require_files = /home/$domain/mail/auto-replies/$local_part
transport = autoreply_transport
no_verify
unseen
virtual_localuser:
driver = accept
require_files = /etc/virtual/$domain/passwd
domains = /etc/virtual/domains
condition = ${lookup {$local_part} lsearch {/etc/virtual/$domain/passwd}{$value}}
transport = virtual_localdelivery
virtual_catchall:
driver = redirect
allow_defer
allow_fail
data = ${lookup {catchall} lsearch {/home/$domain/mail/aliases}}
domains = /etc/virtual/domains
require_files = /home/$domain/mail/aliases
condition = ${lookup {catchall}lsearch{/home/$domain/mail/aliases} {yes}{no}}
qualify_preserve_domain
retry_use_local_part
check_ancestor
one_time
file_transport = address_file
pipe_transport = address_pipe
reply_transport = address_reply
localuser:
driver = accept
check_local_user
condition = ${lookup {$sender_helo_name} lsearch {/etc/virtual/domains}{YES}{NO}}
transport = local_delivery
######################################################################
# TRANSPORTS CONFIGURATION #
######################################################################
# ORDER DOES NOT MATTER #
# Only one appropriate transport is called for each delivery. #
######################################################################
begin transports
remote_smtp_ccio:
driver = smtp
return_path_add = true
interface = 207.112.4.160
helo_data = webmail.ccio.on.ca
remote_smtp_owm:
driver = smtp
helo_data = $sender_address_domain
# interface = ${lookup dnsdb{a=${lookup dnsdb{mxh=$sender_address_domain}}}}
return_path_add = true
remote_smtp_local:
driver = smtp
# interface = ${lookup dnsdb{a=${lookup dnsdb{mxh=$sender_address_domain}}}}
helo_data = $sender_address_domain
return_path_add = true
remote_smtp_alias:
driver = smtp
helo_data = $parent_domain
# interface = ${lookup dnsdb{a=${lookup dnsdb{mxh=$parent_domain}}}}
return_path_add = true
remote_smtp_bounce:
driver = smtp
helo_data = ${lookup dnsdb{defer_never,ptr=$interface_address}{$value}{$primary_hostname}}
# interface = $interface_address
return_path_add = true
autoreply_transport:
driver = pipe
command = /usr/local/bin/autoreply.pl /home/$domain/mail/auto-replies/$local_part
spamcheck:
driver = pipe
command = /usr/local/sbin/exim -oMr spam-scanned -bS
use_bsmtp = true
transport_filter = /usr/local/bin/spamc -u ${lookup{$domain}lsearch{/etc/virtual/domains_users}}
home_directory = "/tmp"
current_directory = "/tmp"
# must use a privileged user to set $received_protocol on the way back in!
user = mailnull
group = mailnull
log_output = true
return_fail_output = false
return_path_add
message_prefix =
message_suffix =
virtual_localdelivery:
driver = appendfile
create_directory = true
directory_mode = 700
file = /var/spool/virtual/${domain}/${local_part}
headers_remove = "Bcc"
return_path_add
user = ${lookup{$domain}lsearch{/etc/virtual/domains_users}}
group = mail
mode = 660
local_delivery:
driver = appendfile
file = /$home/mail/$local_part
delivery_date_add
envelope_to_add
return_path_add
user = mailnull
group = mail
mode = 0660
address_pipe:
driver = pipe
return_output
user = me
address_file:
driver = appendfile
delivery_date_add
envelope_to_add
return_path_add
address_reply:
driver = autoreply
######################################################################
# RETRY CONFIGURATION #
######################################################################
begin retry
# Domain Error Retries
# ------ ----- -------
* quota_7d
* quota F,72h,1h;
* * F,30m,1m; F,90m,5m; F,22h,30m; F,144h,60m
######################################################################
# REWRITE CONFIGURATION #
######################################################################
# There are no rewriting specifications in this default configuration file.
begin rewrite
######################################################################
# AUTHENTICATION CONFIGURATION #
######################################################################
# There are no authenticator specifications in this default configuration file.
begin authenticators
# For Netscape/Mozilla
plain:
driver = plaintext
public_name = PLAIN
server_condition = "${if and{ {!eq{$2}{}}{!eq{$3}{}} \
{crypteq {$3} {${lookup {${local_part:$2}} lsearch \
{/etc/virtual/${domain:$2}/passwd}\
{$value} {*:*}}}} } {1}{0}}"
server_set_id = $2
# For Outlook/Outlook Express
login:
driver = plaintext
public_name = LOGIN
server_prompts = "Username:: : Password::"
server_condition = "${if and{ {!eq{$1}{}}{!eq{$2}{}} \
{crypteq {$2} {${lookup {${local_part:$1}} lsearch \
{/etc/virtual/${domain:$1}/passwd}\
{$value} {*:*}}}} } {1}{0}}"
server_set_id = $1
# End of Exim configuration fileFrom t.baer@??? Wed Oct 28 21:12:31 2009
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Hi Dean,
this sounds really good.
Could you please describe how this works? for example: after 15 failures
the client ist blocked for 2 hours.
If you don`t mind, a sample configuration file would be really helpful.
Thank you very much.
Regards
Torsten
Dean Brooks wrote:
> Here's what we use to automatically control failed authentication
> attempts.
> If you have this in place, your server will automatically begin rejecting
> hosts that send repeated auth failure attempts.
>
> You can change the BADAUTH_LIMIT macro to any rate you like, but we use
> 15 failed attempts in 2 hours as the threshold.
>
> In the global config section of your config:
>
> BADAUTH_LIMIT ?5 / 2h
>
> acl_smtp_connect ?heck_connection
> acl_smtp_quit ?heck_quit
> acl_smtp_notquit ?heck_notquit
>
> In the ACL section of your config:
>
> check_connection:
> drop message Too many failed authentication attempts
> ratelimit ?ADAUTH_LIMIT / noupdate /
> badauth:$sender_host_address
>
> check_quit:
> accept condition ${if eq{$authentication_failed}{1}}
> ratelimit ?ADAUTH_LIMIT / badauth:$sender_host_address
>
> check_notquit:
> accept condition ${if eq{$authentication_failed}{1}}
> ratelimit ?ADAUTH_LIMIT / badauth:$sender_host_address
>
> We need the rate limiting portion in BOTH the "quit" and "notquit"
> sections
> for this to work properly, as you don't know how the connection will
> end up closing.
>
> You also don't want to put the ratelimiting in the RCPT or DATA section,
> because the connection will never get that far (they haven't
> authenticated!).
> You can't put it in the MAIL section either because, again, they haven't
> authenticated.
>
> Thought someone else might find this useful. Rate limits are fun. :)
>
> --
> Dean Brooks
> dean@???
