https://github.com/federicoceratto/dns-firewall
A proxy to inspect and mangle locally generated DNS queries with a Gtk interface.
https://github.com/federicoceratto/dns-firewall
Last synced: 19 days ago
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A proxy to inspect and mangle locally generated DNS queries with a Gtk interface.
- Host: GitHub
- URL: https://github.com/federicoceratto/dns-firewall
- Owner: FedericoCeratto
- Created: 2014-12-22T14:06:26.000Z (over 10 years ago)
- Default Branch: master
- Last Pushed: 2016-05-27T22:59:36.000Z (almost 9 years ago)
- Last Synced: 2025-04-12T07:45:48.056Z (19 days ago)
- Language: Python
- Size: 20.5 KB
- Stars: 3
- Watchers: 2
- Forks: 2
- Open Issues: 0
-
Metadata Files:
- Readme: README.adoc
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README
## DNS firewall
A proxy to inspect and mingle locally generated DNS queries.
Optional tray icon an Gtk interface.
Rationale
---------
Inspecting and filtering DNS traffic generated by desktop applications can be tricky.
Tools like tcpdump have no way to tell which running process generated a DNS query.
Also, Netfilter cannot filter traffic by domain name and many domains resolve to IP addresses that change frequently.
A typical use case is to monitor browser, browsers plugins and extensions for suspicious home-calling or malicious/tracking javascript, or other application leaking data through DNS queries.
dns-firewall acts as a forwarding DNS resolver. It listens locally on port 53 and forwards only the allowed queries to external resolvers.
It detects the name of the process trying to resolve a domain name and applies filtering rules based on that.
Features
--------
* Block DNS queries by application and domain, or return configurable IP addresses
* Tray icon with activity indicators
* Log window to inspect recent activity
* Optionally resolve names using the Tor network
Usage
-----
Create ~/.config/dns-firewall/conf.yaml from conf.yaml.example
Binding to UDP port 53 is required. You can run the process as root or install and configure authbind:
[source,bash]
.conf.yaml.example
----
sudo apt-get install authbind
sudo touch /etc/authbind/byport/53
authbind --depth 2 dns-firewall
# or
sudo dns-firewall
----
Add --tray to enable the tray icon and Gtk interface. Left-click on the tray icon to display the log window.
Update your /etc/resolv.conf with "nameserver 127.0.0.1"
Configuration example
---------------------
[source,python]
.conf.yaml.example
----
# Cache DNS replies
enable_lru_cache: true
lru_cache_size: 100
# Listen on the following IP address and port
host: 127.0.0.1
port: 53
socket_timeout: 20
# DNS resolvers to forward queries to
resolvers: ['208.67.222.222:53', '208.67.220.220:53']
# Use Tor to perform DNS resolution
tor_socks_ipaddr: '127.0.0.1'
tor_socks_port: 9050
# Filtering rules
#
# Like in netfilter, the rules are processed in sequence until a match is found.
# The default values are:
#
# action: drop # Can be accept, nxdomain, return, drop
# dnscrypt: false # Use DNSCrypt
# processname: * # Match process name
# tcp: false # Use TCP instead of UDP
# tor: false # Resolve over Tor
# username: * # Match username
# warn: false # Log match
# zone: * # Match zone
filtering:
# drop all queries to drop.net
- zone: drop.net
action: drop
# resolve a domain using custom resolvers
- zone: custom_resolvers.net
action: accept
resolvers: ['208.67.222.222:53', '208.67.220.220:53']
# return nxdomain for nxdomain.net
- zone: nxdomain.net
action: nxdomain
# return nxdomain to netcat
- processname: nc
action: nxdomain
# return nxdomain to an user
- username: foo
action: nxdomain
# return 127.0.0.1 for return1.net
- zone: return1.net
action: return 127.0.0.1
# resolve in TCP
- zone: tcp.net
action: accept
tcp: true
# resolve using dnscrypt
- zone: dnscrypt.net
dnscrypt: true
action: accept
# resolve using dnscrypt over Tor
- zone: dnscrypt_tor.net
dnscrypt: true
tor: true
action: accept
# resolve using Tor
- zone: tor.net
tor: true
action: accept
# forward every other request to the DNS resolvers, but warn
- action: accept
warn: true
# forward every other request to the DNS resolvers
- action: accept
----
Development status
------------------
In development. Testing and contributions are welcome!