Hosts-Blocker

Hosts-Blocker can be used to block ads, malware and spyware using the hosts file.

Hosts-Blocker comes with a simple command line tool called nhb (node hosts blocker) that can do two things for you:

1. It downloads, merges and sorts hosts files from a configurable list of URLs and generates a new hosts file that aggregates the content of all downloaded hosts files.
2. It runs a small HTTP server that "catches" the redirected HTTP requests.

Installation

The recommended way of installing hosts-blocker is by using using npm:

$ npm install -g hosts-blocker

This will install the nhb executable in your $PATH.

Usage

Configuring Hosts-Blocker

First of all you have to configure a hosts-list and an optional whitelist. You may start with the provided example files:

• hosts-list.example.txt
• whitelist.example.txt

The hosts-list contains a list of URLs (i.e., one URL per line) of hosts files to be downloaded, merged and sorted.

The whitelist contains a list of hostname patterns (i.e., one pattern per line) to be excluded from the generated hosts file. A hostname pattern can either be a simple string or a regular expression.

In this example, we will put both files into the directory /etc/hosts-blocker (i.e., /etc/hosts-blocker/list and /etc/hosts-blocker/whitelist).

Configuring Dnsmasq

First, add the following line to /etc/dnsmasq.conf:

addn-hosts=/etc/hosts.block

This instructs dnsmasq to use /etc/hosts.block as an additional hosts file (besides the ordinary /etc/hosts). Don't forget to reload dnsmasq for activating this new setting!

Generating a hosts file

Next, you can then use the following command to generate the /etc/hosts.block file and tell dnsmasq to reload all registered hosts files (using killall -HUP dnsmasq):

nhb generate \
  --hosts-list /etc/hosts-blocker/list \
  --whitelist /etc/hosts-blocker/whitelist \
  --destination-ip 127.1.1.1 \
  --ui-hostname hosts-blocker.local \
  --output /etc/hosts.block \
&& killall -HUP dnsmasq

You may also want to run this command regularly (e.g., weekly or even daily) using cron.

Starting the catch-all HTTP server

Finally, you may want to start the catch-all HTTP server using the following command:

nhb server \
    --listen-ip 127.1.1.1 \
    --ui-hostname hosts-blocker.local

This HTTP server will "gracefully" return a HTTP 204 (No Content) for any request to any blocked hostname. For example, if the hostname ads.somecompany.com is contained in the blocked hosts file (e.g., /etc/hosts.block) then any request like GET http://ads.somecompany.com/banner.png will return HTTP 204 (No Content).

Note that the (rudimentary) Web-UI, which is available at http://hosts-blocker.local, can be used to get a live view of blocked requests.