unbound(8) Unbound unbound(8)
NAME
unbound - Unbound DNS validating resolver 1.25.0.
SYNOPSIS
unbound [-hdpVv] [-c <cfgfile>]
DESCRIPTION
unbound is a caching DNS resolver.
It uses a built in list of authoritative nameservers for the root zone
(.), the so called root hints. On receiving a DNS query it will ask
the root nameservers for an answer and will in almost all cases receive
a delegation to a top level domain (TLD) authoritative nameserver. It
will then ask that nameserver for an answer. It will recursively
continue until an answer is found or no answer is available (NXDOMAIN).
For performance and efficiency reasons that answer is cached for a
certain time (the answer's time-to-live or TTL). A second query for
the same name will then be answered from the cache. Unbound can also
do DNSSEC validation.
To use a locally running Unbound for resolving put:
nameserver 127.0.0.1
into resolv.conf(5).
If authoritative DNS is needed as well using nsd(8), careful setup is
required because authoritative nameservers and resolvers are using the
same port number (53).
The available options are:
-h Show the version number and commandline option help, and exit.
-c <cfgfile>
Set the config file with settings for unbound to read instead of
reading the file at the default location,
/opt/local/etc/unbound/unbound.conf. The syntax is described in
unbound.conf(5).
-d Debug flag: do not fork into the background, but stay attached
to the console. This flag will also delay writing to the log
file until the thread-spawn time, so that most config and setup
errors appear on stderr. If given twice or more, logging does
not switch to the log file or to syslog, but the log messages
are printed to stderr all the time.
-p Don't use a pidfile. This argument should only be used by
supervision systems which can ensure that only one instance of
Unbound will run concurrently.
-v Increase verbosity. If given multiple times, more information
is logged. This is in addition to the verbosity (if any) from
the config file.
-V Show the version number and build options, and exit.
SEE ALSO
unbound.conf(5), unbound-checkconf(8), nsd(8).
AUTHOR
Unbound developers are mentioned in the CREDITS file in the
distribution.
COPYRIGHT
1999-2026, NLnet Labs
1.25.0 April 29, 2026 unbound(8)
unbound 1.25.0 - Generated Thu Apr 30 08:03:37 CDT 2026