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18 KiB

dns based ad/abuse domain blocking

Description

A lot of people already use adblocker plugins within their desktop browsers, but what if you are using your (smart) phone, tablet, watch or any other wlan gadget...getting rid of annoying ads, trackers and other abuse sites (like facebook ;-) is simple: block them with your router. When the dns server on your router receives dns requests, you will sort out queries that ask for the resource records of ad servers and return a simple 'NXDOMAIN'. This is nothing but Non-eXistent Internet or Intranet domain name, if domain name is unable to resolved using the dns server, a condition called the 'NXDOMAIN' occurred.

Main Features

  • support of the following domain block list sources (free for private usage, for commercial use please check their individual licenses):
    • adaway
    • => infrequent updates, approx. 400 entries (enabled by default)
    • adguard
    • => numerous updates on the same day, approx. 12.000 entries
    • blacklist
    • => static local blacklist, located by default in '/etc/adblock/adblock.blacklist'
    • disconnect
    • => numerous updates on the same day, approx. 6.500 entries (enabled by default)
    • dshield
    • => daily updates, approx. 4.500 entries
    • feodotracker
    • => daily updates, approx. 0-10 entries
    • hphosts
    • => monthly updates, approx. 50.000 entries
    • malwaredomains
    • => daily updates, approx. 16.000 entries
    • malwaredomainlist
    • => daily updates, approx. 1.500 entries
    • openphish
    • => numerous updates on the same day, approx. 1.800 entries
    • ransomware tracker
    • => daily updates, approx. 150 entries
    • reg_cn
    • => regional blocklist for China, daily updates, approx. 1.600 entries
    • reg_id
    • => regional blocklist for Indonesia, daily updates, approx. 800 entries
    • reg_nl
    • => regional blocklist for the Netherlands, weekly updates, approx. 1300 entries
    • reg_pl
    • => regional blocklist for Poland, daily updates, approx. 50 entries
    • reg_ro
    • => regional blocklist for Romania, weekly updates, approx. 600 entries
    • reg_ru
    • => regional blocklist for Russia, weekly updates, approx. 2.000 entries
    • securemecca
    • => infrequent updates, approx. 25.000 entries
    • shallalist (categories "adv" "costtraps" "spyware" "tracker" "warez" enabled by default)
    • => daily updates, approx. 32.000 entries (a short description of all shallalist categories can be found online)
    • spam404
    • => infrequent updates, approx. 5.000 entries
    • sysctl/cameleon
    • => weekly updates, approx. 21.000 entries
    • whocares
    • => weekly updates, approx. 12.000 entries
    • winhelp
    • => infrequent updates, approx. 15.000 entries
    • winspy
    • => infrequent updates, approx. 120 entries
    • yoyo
    • => weekly updates, approx. 2.500 entries (enabled by default)
    • zeus tracker
    • => daily updates, approx. 440 entries
  • zero-conf like automatic installation & setup, usually no manual changes needed
  • simple but yet powerful adblock engine: adblock does not use error prone external iptables rulesets, http pixel server instances and things like that
  • supports five different dns backends / block list formats: dnsmasq, unbound, named (bind), kresd and dnscrypt-proxy
  • automatically selects uclient-fetch or wget as download utility (other tools like curl or aria2c are supported as well)
  • provides 'http only' mode without installed ssl library for all non-SSL block list sources
  • supports a wide range of router modes, even AP modes are supported
  • full IPv4 and IPv6 support
  • provides top level domain compression ('tld compression'), this feature removes thousands of needless host entries from the block list and lowers the memory footprint for the dns backends
  • each block list source will be updated and processed separately
  • block list source parsing by fast & flexible regex rulesets
  • overall duplicate removal in central block list (adb_list.overall)
  • additional whitelist for manual overrides, located by default in /etc/adblock/adblock.whitelist
  • quality checks during block list update to ensure a reliable dns backend service
  • minimal status & error logging to syslog, enable debug logging to receive more output
  • procd based init system support (start/stop/restart/reload/suspend/resume/query/status)
  • procd network interface trigger support or classic time based startup
  • suspend & resume adblock actions temporarily without block list reloading
  • output comprehensive runtime information via LuCI or via 'status' init command
  • query function to quickly identify blocked (sub-)domains, e.g. for whitelisting
  • strong LuCI support
  • optional: force dns requests to local resolver
  • optional: force overall sort / duplicate removal for low memory devices (handle with care!)
  • optional: 'manual mode' to re-use blocklist backups during startup, get fresh lists only via manual reload or restart action
  • optional: automatic block list backup & restore, they will be used in case of download errors or during startup in manual mode
  • optional: add new adblock sources on your own via uci config

Prerequisites

  • LEDE project, tested with latest stable release (LEDE 17.01) and with current LEDE snapshot
  • a usual setup with an enabled dns backend at minimum - dump AP modes without a working dns backend are not supported
  • a download utility:
    • to support all blocklist sources a full version (with ssl support) of 'wget', 'uclient-fetch' with one of the 'libustream-*' ssl libraries, 'aria2c' or 'curl' is required
    • for limited devices with real memory constraints, adblock provides also a 'http only' option and supports wget-nossl and uclient-fetch (without libustream-ssl) as well
    • for more configuration options see examples below

Installation & Usage

  • install 'adblock' (opkg install adblock)
  • at minimum configure the appropriate dns backend ('dnsmasq' by default) and enable the adblock service in /etc/config/adblock
  • control the adblock service manually with /etc/init.d/adblock start/stop/restart/reload/suspend/resume/status or use the LuCI frontend

LuCI adblock companion package

  • for easy management of the various block list sources and all other adblock options you should use the provided LuCI frontend
  • install 'luci-app-adblock' (opkg install luci-app-adblock)
  • the application is located in LuCI under 'Services' menu

Tweaks

  • runtime information: the adblock status is available via /etc/init.d/adblock status (see example below)
  • debug logging: for script debugging please set the config option 'adb_debug' to '1' and check the runtime output with logread -e "adblock"
  • storage expansion: to process and store all block list sources at once it might helpful to enlarge your temp directory with a swap partition => see openwrt wiki for further details
  • add white- / blacklist entries: add domain white- or blacklist entries to always-allow or -deny certain (sub) domains, by default both lists are empty and located in /etc/adblock. Please add one domain per line - ip addresses, wildcards & regex are not allowed (see example below)
  • backup & restore block lists: enable this feature, to restore automatically the latest compressed backup of your block lists in case of any processing error (e.g. a single block list source is not available during update). Please use an (external) solid partition and not your volatile router temp directory for this
  • scheduled list updates: for a scheduled call of the adblock service add an appropriate crontab entry (see example below)
  • change startup behaviour: by default the startup will be triggered by the 'wan' procd interface trigger. Choose 'none' to disable automatic startups, 'timed' to use a classic timeout (default 30 sec.) or select another trigger interface.
  • suspend & resume adblocking: to quickly switch the adblock service 'on' or 'off', simply use /etc/init.d/adblock [suspend|resume]
  • domain query: to query the active block list for a specific domain, please run /etc/init.d/adblock query <DOMAIN> (see example below)
  • add new list sources: you could add new block list sources on your own via uci config, all you need is a source url and an awk one-liner (see example below)
  • disable active dns probing in windows 10: to prevent a yellow exclamation mark on your internet connection icon (which wrongly means connected, but no internet), please change the following registry key/value from "1" to "0" HKLM\SYSTEM\CurrentControlSet\Services\NlaSvc\Parameters\Internet\EnableActiveProbing

Further adblock config options

  • usually the pre-configured adblock setup works quite well and no manual config overrides are needed, all listed options apply to the 'global' config section:
    • adb_enabled => main switch to enable/disable adblock service (default: '0', disabled)
    • adb_debug => enable/disable adblock debug output (default: '0', disabled)
    • adb_dns => select the dns backend for your environment: 'dnsmasq', 'unbound', 'named', 'kresd' or 'dnscrypt-proxy' (default: 'dnsmasq')
    • adb_dnsdir => target directory for the generated blocklist 'adb_list.overall' (default: not set, use dns backend default)
    • adb_trigger => set the startup trigger to a certain interface, to 'timed' or to 'none' (default: 'wan')
    • adb_triggerdelay => additional trigger delay in seconds before adblock processing begins (default: '1')
    • adb_fetch => full path to a dedicated download utility, see example below (default: not set, use wget default)
    • adb_fetchparm => options for the download utility, see example below (default: not set, use wget default options)
    • adb_forcedns => force dns requests to local resolver (default: '0', disabled)
    • adb_forcesrt => force overall sort on low memory devices with less than 64 MB RAM (default: '0', disabled)
    • adb_manmode => do not automatically update block lists during startup, use backups instead (default: '0', disabled)

Examples

change default dns backend to 'unbound':

Adblock deposits the sorted and filtered block list (adb_list.overall) in '/var/lib/unbound' where unbound can find them in its jail. If you use manual configuration for unbound, then just include the following line in your 'server' clause:


  include: "/var/lib/unbound/adb_list.overall"

change default dns backend to 'named' (bind):

Adblock deposits the sorted and filtered block list (adb_list.overall) in '/var/lib/bind' where bind can find them. To use the block list please modify the following bind configuration files:


change '/etc/bind/named.conf', in the 'options' namespace add:
  response-policy { zone "rpz"; };

and at the end of the file add:
  zone "rpz" {
    type master;
    file "/etc/bind/db.rpz";
    allow-query { none; };
    allow-transfer { none; };
  };

create the new file '/etc/bind/db.rpz' and add:
  $TTL 2h
  $ORIGIN rpz.
  @ SOA localhost. root.localhost. (1 6h 1h 1w 2h)
  NS localhost.

  $INCLUDE /var/lib/bind/adb_list.overall

change default dns backend to 'kresd':

The knot-resolver (kresd) is only available on turris omnia devices. Currently there's no package for kresd in the official LEDE / OpenWrt package repository. Adblock deposits the sorted and filtered block list (adb_list.overall) in '/etc/kresd' where kresd can find them. To use the block list please create/modify the following kresd configuration files:


TurrisOS > 3.6:
  edit '/etc/config/resolver' and change / uncomment the following options:
    forward_upstream '0'
    list rpz_file '/etc/kresd/adb_list.overall'

TurrisOS < 3.6:
  edit '/etc/config/resolver' and change / uncomment the following options:
   forward_upstream '0'
   option include_config '/etc/kresd/custom.conf'

  create '/etc/kresd/custom.conf' and add:
    policy.add(policy.rpz(policy.DENY, '/etc/kresd/adb_list.overall'))
    policy.add(policy.all(policy.FORWARD({'8.8.8.8', '8.8.4.4'})))

change default dns backend to 'dnscrypt-proxy':

Adblock deposits the sorted and filtered block list (adb_list.overall) by default in '/tmp' where DNSCrypt-Proxy can find them. The blacklist option is not supported by default, because DNSCrypt-Proxy is compiled without plugins support. Take a custom LEDE build with plugins support to use this feature:


edit '/etc/config/dnscrypt-proxy' and add the following option per dnscrypt-proxy instance:
  list blacklist 'domains:/tmp/adb_list.overall'

configuration for different download utilities:


wget (default):
  option adb_fetch '/usr/bin/wget'
  option adb_fetchparm '--quiet --no-cache --no-cookies --max-redirect=0 --timeout=10 --no-check-certificate -O'

aria2c:
  option adb_fetch '/usr/bin/aria2c'
  option adb_fetchparm '-q --timeout=10 --allow-overwrite=true --auto-file-renaming=false --check-certificate=false -o'

uclient-fetch:
  option adb_fetch '/bin/uclient-fetch'
  option adb_fetchparm '-q --timeout=10 --no-check-certificate -O'

curl:
  option adb_fetch '/usr/bin/curl'
  option adb_fetchparm '-s --connect-timeout 10 --insecure -o'

receive adblock runtime information:


/etc/init.d/adblock status
::: adblock runtime information
  + adblock_status  : enabled
  + adblock_version : 3.0.0
  + blocked_domains : 37406
  + fetch_utility   : wget (built-in)
  + dns_backend     : kresd (/etc/kresd)
  + last_rundate    : 08.09.2017 21:21:21
  + system_release  : OpenWrt omnia 15.05

cronjob for a regular block list update (/etc/crontabs/root):


0 06 * * *    /etc/init.d/adblock reload

blacklist entry (/etc/adblock/adblock.blacklist):


ads.example.com

This entry blocks the following (sub)domains:
  http://ads.example.com/foo.gif
  http://server1.ads.example.com/foo.gif
  https://ads.example.com:8000/

This entry does not block:
  http://ads.example.com.ua/foo.gif
  http://example.com/

whitelist entry (/etc/adblock/adblock.whitelist):


here.com

This entry removes the following (sub)domains from the block list:
  maps.here.com
  here.com

This entry does not remove:
  where.com
  www.adwhere.com

query active block list for a certain (sub-)domain, e.g. for whitelisting:


/etc/init.d/adblock query example.www.doubleclick.net
root@turris:~# /etc/init.d/adblock query example.www.doubleclick.net
::: max. ten results for domain 'example.www.doubleclick.net'
  - no match
::: max. ten results for domain 'www.doubleclick.net'
  - no match
::: max. ten results for domain 'doubleclick.net'
  + doubleclick.net

The query function checks against the submitted (sub-)domain and recurses automatically to the upper top level domain.
For every (sub-)domain it returns the first ten relevant results.
In the example above whitelist "doubleclick.net" to free the submitted domain.

add a new block list source:


1. the easy way ...
example: https://easylist-downloads.adblockplus.org/rolist+easylist.txt
adblock already supports an easylist source, called 'ruadlist'. To add the additional local easylist
as a new source, copy the existing config source 'ruadlist' section and change only
the source name, the url and the description - that's all!

config source 'rolist'
  option enabled '0'
  option adb_src 'https://easylist-downloads.adblockplus.org/rolist+easylist.txt'
  option adb_src_rset '{FS=\"[|^]\"} \$0 ~/^\|\|([A-Za-z0-9_-]+\.){1,}[A-Za-z]+\^$/{print tolower(\$3)}'
  option adb_src_desc 'focus on romanian ad related domains plus generic easylist additions, weekly updates, approx. 600 entries'

2. a bit harder ...
to add a really new source with different domain/host format you have to write a suitable
awk one-liner on your own, so basic awk skills are needed. As a starting point check the already
existing awk strings (adb_src_rset) in adblock config, maybe you need only small changes for your individual list.
Download the desired list and test your new awk string locally with:
  cat new.list | awk 'fs__individual search__search core__result'
  'fs' => field separator (optional)
  'individual search' => individual search part to filter out needless list information
  'search core' => always '([A-Za-z0-9_-]+\.){1,}[A-Za-z]+', this is part of all list sources and should be unchanged
  'result' => always '{print tolower(\$n)}', only the output column 'n' may vary
the output result should be a sequential list with one domain/host per line - nothing more.

If your awk one-liner works quite well, add a new source section in adblock config and test your new source

Support

Please join the adblock discussion in this forum thread or contact me by mail dev@brenken.org

Removal

  • stop all adblock related services with /etc/init.d/adblock stop
  • optional: remove the adblock package (opkg remove adblock)

Have fun!
Dirk