UNWIND(8)

NAME
unwind - validating DNS resolver

SYNOPSIS
unwind [-dnv] [-f file] [-s socket]

DESCRIPTION
unwind is a validating DNS resolver. It is intended to run on client machines like workstations or laptops and only listens on localhost. unwind sends DNS queries to nameservers to answer queries and switches to resolvers learned from dhclient(8) if it detects that DNS queries are blocked by the local network. It periodically probes if DNS is no longer blocked and switches back to querying nameservers itself.

unwind keeps the DNS answers in a cache shared by the different DNS name server types. unwind manages the cache size by deleting oldest entries when needed. The cache is non-configurable and is lost upon process restart.

To have unwind enabled at boot time, use “rcctl enable unwind”, which sets

    unwind_flags=""

in rc.conf.local(8).

Adding

    supersede domain-name-servers 127.0.0.1;

to /etc/dhclient.conf configures a machine using DHCP to use unwind.

A running unwind can be controlled with the unwindctl(8) utility.

The options are as follows:

-d  Do not daemonize. If this option is specified, unwind will run in the foreground and log to stderr.

-f file
    Specify an alternative configuration file.

-n  Configtest mode. Only check the configuration file for validity.

-s socket
    Use an alternate location for the default control socket.

-v  Produce more verbose output. Multiple -v options increase the verbosity. Debug output from libunbound is only available when logging to stderr.

FILES
/etc/unwind.conf
    Default unwind configuration file.
/var/db/unwind.key
    Trust anchor for DNSSEC validation.
/dev/unwind.sock
    UNIX-domain socket used for communication with unwindctl(8).

SEE ALSO
unwind.conf(5), dhclient(8), unbound(8), unwindctl(8)

STANDARDS
P. Mockapetris, November 1987, RFC 1034, DOMAIN NAMES - CONCEPTS AND FACILITIES.

P. Mockapetris, November 1987, RFC 1035, DOMAIN NAMES - IMPLEMENTATION AND SPECIFICATION.

HISTORY
The unwind program first appeared in OpenBSD 6.5.

AUTHORS
-nosplit The unwind program was written by Florian Obser <florian@openbsd.org>.