Maintained by: NLnet Labs

Unbound: Howto Statistics

By W.C.A. Wijngaards, NLnet Labs, March 2009.

This how to contains a guide for configuring statistics in unbound. Below, statistics with Munin and Cacti is shown. Other systems than the ones listed here are possible, this is an example.


Unbound has an option to enable extended statistics collection. If enabled, more statistics are collected, for example what types of queries are sent to the resolver. Otherwise, only the total number of queries is collected.

Statistics can be printed to the log file using the statistics-interval, but this howto concentrates on using unbound-control to obtain statistics on demand. If you set a statistics-interval, every interval it is printed to the logfile.

To use unbound-control, first setup unbound control (use the unbound-control-setup script). See howto setup unbound. Then you can use the unbound-control stats command to print out the statistics on demand.

Various graphing tools expect the counters to go up over time. Some may expect counters to be reset to 0 since the previous statistics printout. The statistics-cumulative option controls unbounds behaviour. By default it is set to no, which resets values to zero after stat printout.

# enable extended statistics.
        statistics-interval: 0
        extended-statistics: yes
        # set to yes if graphing tool needs it
        statistics-cumulative: no 

Statistics with Munin

In the contrib directory in the source of unbound is the unbound_munin_ plugin script. It can be used with munin to monitor the health of an unbound server.

Install munin and munin-node with the appropriate package install tool. The plugin script for unbound can be copied somewhere on the system (such as in the unbound directory). Then create symbolic links from /etc/munin/plugins to that file.

$ ln -s /etc/unbound/unbound_munin_ /etc/munin/plugins/unbound_munin_hits

In the /etc/munin/plugin-conf.d/plugins.conf file you can setup the unbound munin plugin. Below are the default values. Set the correct values for your system. The statefile is a temporary file.

user root
env.statefile /usr/local/var/munin/plugin-state/unbound-state
env.unbound_conf /usr/local/etc/unbound/unbound.conf
env.unbound_control /usr/local/sbin/unbound-control
env.spoof_warn 1000
env.spoof_crit 100000

Restart the munin-node daemon. Munin will automatically pick up the new graph and plot it with rrdtool.

Additional graphs are possible, below is a list of them, and examples. Create (additional) symbolic links to unbound_munin_ with the names (in bold) of those graphs to enable their display. Several require that extended-statistics is enabled in config. Pictures included are samples, your statistics may look different :-) .

unbound_munin_hits - base volume, cache hits, unwanted traffic

A sharp increase in unwanted traffic indicates a possible spoof run in progress.

unbound_munin_queue - to monitor the internal requestlist

unbound_munin_memory - memory usage

You can see that the server was restarted during the day.

unbound_munin_by_type - incoming queries by type

The types received are shown.

unbound_munin_by_class - incoming queries by class

Usually only IN (internet) class.

unbound_munin_by_opcode - incoming queries by opcode

Usually only QUERY (normal query).

unbound_munin_by_rcode - answers by rcode, validation status

unbound_munin_by_flags - incoming queries by flags

unbound_munin_histogram - histogram of query resolving times

Statistics with Cacti

The setup is described in the README in the tarball in the unbound source contrib directory: contrib/unbound_cacti.tar.gz (contributed by Dmitriy Demidov). Updated versions may be found here (

Example output from unbound cacti statistics