Unbound has a vast array of configuration options for advanced use cases, which can seem a little overwhelming at first. Luckily, all of the defaults are sensible and secure, so in a lot of environments you can run Unbound without changing any options. Below we will go through a basic, recommended config, but feel free to add and experiment with options as you need them.
The instructions in this page assume that Unbound is already installed.
The basic configuration which you can use out of the box is shown below. To use it, you need to create a file with this config as its content (or copy the config to the default config file which can be found during the installation process).
server: # can be uncommented if you do not need user privilige protection # username: "" # can be uncommented if you do not need file access protection # chroot: "" # location of the trust anchor file that enables DNSSEC. note that # the location of this file can elsewhere auto-trust-anchor-file: "/usr/local/etc/unbound/root.key" # auto-trust-anchor-file: "/var/lib/unbound/root.key" # send minimal amount of information to upstream servers to enhance privacy qname-minimisation: yes # specify the interfaces to answer queries from by ip-address. interface: 0.0.0.0 # interface: ::0 # addresses from the IP range that are allowed to connect to the resolver access-control: 192.168.0.0/16 allow # access-control: 2001:DB8/64 allow
By default the Unbound config uses chroot to provide an extra layer of defence
against remote exploits. If Unbound is not starting because it cannot access
files due to permission errors caused by chroot, a solution can be to
enter file paths as full pathnames starting at the root of the filesystem
/). Otherwise, if chroot is not required you can disable it in
# disable chroot chroot: ""
By default Unbound assumes that a user named “unbound” exists, which you can add
this user with an account management tool available on your system. You can also
disable this feature by adding
username: "" in the config. If it is enabled,
after the setup, any other user privileges are dropped and the configured
username is assumed. If this user needs access to files (such as the ‘trust
anchor’ mentioned below) these can be created by executing with
unbound in front of it.
Unbound comes with the unbound-checkconf(8) tool. This tool allows you to check the config file for errors before starting Unbound. It is very convenient because if any errors are found it tells you where they are, which is particularly useful when Unbound is already running to avoid failure to restart due to a configuration error.
Set up Remote Control¶
A useful functionality to enable is the use of the unbound-control
command. This allows command makes starting, stopping, and reloading Unbound
easier. To enable this functionality we need to add
remote-control to the
config and enable it.
remote-control: # enable remote-control control-enable: yes # location of the files created by unbound-control-setup # server-key-file: "/usr/local/etc/unbound/unbound_server.key" # server-cert-file: "/usr/local/etc/unbound/unbound_server.pem" # control-key-file: "/usr/local/etc/unbound/unbound_control.key" # control-cert-file: "/usr/local/etc/unbound/unbound_control.pem"
To use the unbound-control command, we need to invoke the
unbound-control-setup command. This creates a number of files in the
default install directory. The default install directory is
/usr/local/etc/unbound/ on most systems, but some distributions may put it
Apart from an extensive config file, with just about all the possible configuration options, unbound-control-setup creates the cryptographic keys necessary for the control option.
If you use a username like
unbound in the config to run the daemon (which is
the default setting), you can use sudo to create the files in that
user’s name, so that the user running Unbound is allowed to read the keys. This
is also a solution if the
/usr/local/etc/unbound/ (or any other default
direcotry) directory is write-protected, which is the case for some
sudo -u unbound unbound-control-setup
You can now control Unbound using the unbound-control command. Note
that if your configuration file is not in the default location or not named
unbound.conf, the name (and possibly path) need to be provided when using
the command using the
Set up Trust Anchor (Enable DNSSEC)¶
To enable DNSSEC, which we strongly recommend, we need to set up a trust anchor as it allows the verification of the integrity of the responses to the queries you send.
To help, we can use the unbound-anchor command.
unbound-anchor performs the setup by configuring a trust anchor. This
trust anchor will only serve as the initial anchor from builtin values. To keep
this anchor up to date, Unbound must be able to read and write to this file. The
default location that unbound-anchor creates this in is determined by
your installation method. Usually the default directory is
Note that using a package manager to install Unbound, on some distributions,
creates the root key during installation. On Ubuntu 20.04.1 LTS for example,
this location is
/var/lib/unbound/root.key. On macOS Big Sur this location
/opt/homebrew/etc/unbound/root.key If you create the root key yourself
(by using the unbound-anchor command), then the path to the anchor
file in the configuration file should be changed to the correct location. To
find out the default location you can use the unbound-anchor command
again with the
-vvv option enabled. To enable DNSSEC, we add
auto-trust-anchor-file under the
server options in the config.
# enable DNSSEC auto-trust-anchor-file: "/var/lib/unbound/root.key"
Note that on some systems the
/usr/local/etc/unbound/ directory might be
If the unbound-control-setup command fails due to the insufficient
permissions, run the command as the correct user, here we use the user
unbound as this is the default user.
sudo -u unbound unbound-anchor
This step is also important when using the