In this mode, the only dependency is OpenSSL (version 1.0.2 or later is required for hostname authentication to be supported). If this is installed in a non-standard location on your system use the --with-ssl option to configure below to specify where it is.
It may be necessary to install 1.0.2 from source for most Linux distros.
It is recommended to install OpenSSL using homebrew, in which case use the following in the configure line in 1.3 below:
Download the getdns source
> git clone https://github.com/getdnsapi/getdns.git
> cd getdns
> git checkout release/1.1.0a2
Build the code
> git submodule update --init
> libtoolize -ci
> autoreconf -fi
> mkdir build
> cd build
> ../configure --prefix=<install_location> --without-libidn --enable-stub-only
- If you want to see very detailed debug information as messages are processed (including connection statistics) then add the --enable-debug-stub option to the configure line above.
- If you just want to see connection statistics then use the --enable-debug-daemon option instead to the configure line above.
Run the daemon
The command below will run the daemon listening on port 53 of the loopback address and sending queries to the NLnet Labs test DNS Privacy server (at 18.104.22.168 and 2a04:b900:0:100::38) over TLS. (More test servers are listed here).
It also specifies an example idle timeout on the TLS connection of 10s with the '-e 10000' option. (Note: the NLnet Labs test server does not support EDNS0 TCP Keepalive yet, so in that case this timeout will always be used.)
It is recommended to use more than one upstream for increased performance and reliability.
> sudo src/tools/getdns_query -s @22.214.171.124 -l L -z 127.0.0.1@53 -e 10000
IPv4 and IPv6
> sudo src/tools/getdns_query -s @126.96.36.199 @2a04:b900:0:100::38 -l L -z 127.0.0.1@53 -z ::1@53 -e 10000
You can specify multiple upstreams just by repeating the @<address> element on the command line.
Exit the daemon at any time by hitting CTRL-C.
Strict vs Opportunistic
The above command will run the daemon without trying to authenticate the TLS connection (a form of Opportunistic Privacy).
If you have authentication information for the DNS Privacy server and you want to use Strict Privacy then you can specify this when starting the daemon in the following ways:
- Domain name: append the domain name to the IP address with a tilde '~' e.g. @188.8.131.52~getdnsapi.net and add the '-m' flag
- SPKI pinset: specify the pinset using the '-K' flag e.g. -K 'pin-sha256="foxZRnIh9gZpWnl+zEiKa0EJ2rdCGroMWm02gaxSc9S="' and add the '-m' flag
Test the daemon
A quick test can be done by using dig on the loopback address
> dig @127.0.0.1 www.example.com
Modify your upstream resolvers
For getdns to re-send outgoing DNS queries over TLS the recursive resolvers configured on your machine must be changed to send all the local queries over the loopback interface on which getdns is listening. This depends on the operating system being run. It is useful to note your existing default nameservers before making this change!
From the command line you can do the following to set the local DNS servers on, for example, your 'Wi-Fi' interface (first line clears all servers, second line adds localhost):
sudo networksetup -setdnsservers Wi-Fi Empty
sudo networksetup -setdnsservers Wi-Fi 127.0.0.1 ::1
If you want to reset, use something similar to the above to specify your default servers.
Or via the GUI:
- Open System Preferences->Network->Advanced->DNS
- Use the '-' button to remove the existing nameservers
- Use the + button to add '127.0.0.1' and '::1' (only add the IPv4 address if you don't have IPv6)
- Hit 'OK' in the DNS pane and then 'Apply' on the Network pane
Once the change in step 1.6 is made your queries will be re-directed to the getdns daemon and sent over TLS! You can monitor the traffic using Wireshark watching on port 853.
- You may need to restart some applications to have them pick up the network settings
- If you are using a DNS Privacy server that does not support concurrent processing of TLS queries, you may experience some issues due to timeouts causing subsequent queries on the same connection to fail.
- The daemon currently (indefinitely) backs-off servers that provide poor service - the next version will have a timed re-try in this case.