.\" $OpenBSD: unwind.conf.5,v 1.33 2023/02/21 07:47:24 jmc Exp $ .\" .\" Copyright (c) 2018 Florian Obser .\" Copyright (c) 2005 Esben Norby .\" Copyright (c) 2004 Claudio Jeker .\" Copyright (c) 2003, 2004 Henning Brauer .\" Copyright (c) 2002 Daniel Hartmeier .\" .\" Permission to use, copy, modify, and distribute this software for any .\" purpose with or without fee is hereby granted, provided that the above .\" copyright notice and this permission notice appear in all copies. .\" .\" THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES .\" WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF .\" MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR .\" ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES .\" WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN .\" ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF .\" OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. .\" .Dd $Mdocdate: February 21 2023 $ .Dt UNWIND.CONF 5 .Os .Sh NAME .Nm unwind.conf .Nd validating DNS resolver configuration file .Sh DESCRIPTION The .Xr unwind 8 daemon is a validating DNS resolver. .Pp The .Nm config file is divided into the following main sections: .Bl -tag -width xxxx .It Sy Macros User-defined variables may be defined and used later, simplifying the configuration file. .It Sy Global Configuration Global settings for .Xr unwind 8 . .El .Pp Additional configuration files can be included with the .Ic include keyword. .Sh MACROS Macros can be defined that will later be expanded in context. Macro names must start with a letter, digit, or underscore, and may contain any of those characters. Macro names may not be reserved words (for example, .Ic forwarder , .Ic port , or .Ic DoT ) . Macros are not expanded inside quotes. .Pp For example: .Bd -literal -offset indent fwd1=192.0.2.53 fwd2=192.0.2.153 forwarder { $fwd1 $fwd2 } .Ed .Sh GLOBAL CONFIGURATION .Bl -tag -width Ds .It Ic block list Ar file Op Cm log A file containing domains to block, one per line. If a domain from this list is queried, .Nm unwind answers with a return code of .Dv REFUSED . With .Cm log blocked queries are logged. .It Ic forwarder Brq Ar address Oo Ic port Ar number Oc Oo Oo Ic authentication name Ar name Oc Ic DoT Oc ... A list of addresses of DNS name servers to forward queries to. .Ic port defaults to 53. If .Ic DoT is specified, use DNS over TLS when sending queries to the server at .Ar address . The default .Ic port is 853. .Ar name validates the certificate of the DNS over TLS server. .It Ic preference Brq Ar type ... A list of DNS name server types to specify the order in which name servers are picked when measured round-trip time medians are equal. Additionally, the first mentioned type gets a time bonus. Validating name servers are always picked over non-validating name servers. DNS name server types are, in default order of preference: .Bl -tag -width "oDoT-forwarder" .It Ic DoT DNS over TLS name servers configured in .Nm . .It Ic oDoT-forwarder Name servers configured in .Nm . .Nm unwind tries to opportunistically use DNS over TLS. .It Ic forwarder Name servers configured in .Nm . .It Ic recursor .Nm unwind itself recursively resolves names. .It Ic oDoT-autoconf Name servers learned from autoconfiguration. A list of sources for proposals learned through autoconfiguration is documented in .Xr resolvd 8 . .Nm unwind tries to opportunistically use DNS over TLS. .It Ic autoconf Name servers learned from autoconfiguration. .It Ic stub Name servers learned from autoconfiguration, queried using the libc functions (see .Xr asr_run 3 ) . Will never validate. Useful when running behind broken middle boxes that do not like edns0. DNS answers from stub name servers are not cached. .El .It Ic force Oo Cm accept bogus Oc Ar type Brq Ar name ... Force resolving of .Ar name and its subdomains by the given resolver .Ar type . If .Cm accept bogus is specified, validation is not enforced. .El .Sh FILES .Bl -tag -width "/etc/unwind.conf" -compact .It Pa /etc/unwind.conf The default .Xr unwind 8 configuration file. .El .Sh EXAMPLES Block requests for domains in .Pa /etc/blocklist and log each blocked request: .Bd -literal -offset indent block list "/etc/blocklist" log .Ed .Pp Define a DNS over TLS (DoT) forwarder and make it the preferred resolver: .Bd -literal -offset indent forwarder { 192.168.1.250 port 8080 authentication name "resolver.local" DoT } preference { DoT } .Ed .Pp Where a domain requires a specific nameserver and it may only exist in a nameserver available on the local network, force .Xr unwind 8 to use a specific resolver type: .Bd -literal -offset indent force autoconf { domain.local } .Ed .Sh SEE ALSO .Xr rc.conf.local 8 , .Xr unwind 8 , .Xr unwindctl 8 .Sh HISTORY The .Nm file format first appeared in .Ox 6.5 .