RESOLVCONF(8)		  BSD System Manager's Manual		 RESOLVCONF(8)

NAME
     resolvconf — a framework for managing multiple DNS configurations

SYNOPSIS
     resolvconf -I
     resolvconf [-m metric] [-p] [-x] -a interface[.protocol] <file
     resolvconf [-f] -d interface[.protocol]
     resolvconf [-x] -il pattern
     resolvconf -u

DESCRIPTION
     resolvconf manages resolv.conf(5) files from multiple sources, such as
     DHCP and VPN clients.  Traditionally, the host runs just one client and
     that updates /etc/resolv.conf.  More modern systems frequently have wired
     and wireless interfaces and there is no guarantee both are on the same
     network.  With the advent of VPN and other types of networking daemons,
     many things now contend for the contents of /etc/resolv.conf.

     resolvconf solves this by letting the daemon send their resolv.conf(5)
     file to resolvconf via stdin(3) with the argument -a interface[.protocol]
     instead of the filesystem.  resolvconf then updates /etc/resolv.conf as
     it thinks best.  When a local resolver other than libc is installed, such
     as dnsmasq(8) or named(8), then resolvconf will supply files that the
     resolver should be configured to include.

     resolvconf assumes it has a job to do.  In some situations resolvconf
     needs to act as a deterrent to writing to /etc/resolv.conf.  Where this
     file cannot be made immutable or you just need to toggle this behaviour,
     resolvconf can be disabled by adding resolvconf=NO to resolvconf.conf(5).

     resolvconf can mark an interfaces resolv.conf as private.	This means
     that the name servers listed in that resolv.conf are only used for
     queries against the domain/search listed in the same file.  This only
     works when a local resolver other than libc is installed.	See
     resolvconf.conf(5) for how to configure resolvconf to use a local name
     server.

     resolvconf can mark an interfaces resolv.conf as exclusive.  Only the
     latest exclusive interface is used for processing, otherwise all are.

     When an interface goes down, it should then call resolvconf with -d
     interface.* arguments to delete the resolv.conf file(s) for all the
     protocols on the interface.

     Here are some more options that resolvconf has:-

     -I      Initialise the state directory /var/run/resolvconf.  This only
	     needs to be called if the initial system boot sequence does not
	     automatically clean it out; for example the state directory is
	     moved somewhere other than /var/run.  If used, it should only be
	     called once as early in the system boot sequence as possible and
	     before resolvconf is used to add interfaces.

     -f      Ignore non existant interfaces.  Only really useful for deleting
	     interfaces.

     -i pattern
	     List the interfaces and protocols, optionally matching pattern,
	     we have resolv.conf files for.

     -l pattern
	     List the resolv.conf files we have.  If pattern is specified then
	     we list the files for the interfaces and protocols that match it.

     -m metric
	     Set the metric of the interface when adding it, default of 0.
	     Lower metrics take precedence.  This affects the default order of
	     interfaces when listed.

     -p      Marks the interface resolv.conf as private.

     -u      Force resolvconf to update all its subscribers.  resolvconf does
	     not update the subscribers when adding a resolv.conf that matches
	     what it already has for that interface.

     -x      Mark the interface resolv.conf as exclusive when adding, other‐
	     wise only use the latest exclusive interface.

     resolvconf also has some options designed to be used by its subscribers:-

     -v      Echo variables DOMAINS, SEARCH and NAMESERVERS so that the sub‐
	     scriber can configure the resolver easily.

     -V      Same as -v except that only the information configured in
	     resolvconf.conf(5) is set.

INTERFACE ORDERING
     For resolvconf to work effectively, it has to process the resolv.confs
     for the interfaces in the correct order.  resolvconf first processes
     interfaces from the interface_order list, then interfaces without a metic
     and that match the dynamic_order list, then interfaces with a metric in
     order and finally the rest in the operating systems lexical order.  See
     resolvconf.conf(5) for details on these lists.

PROTOCOLS
     Here are some suggested protocol tags to use for each resolv.conf file
     registered on an interface:-

     dhcp    Dynamic Host Configuration Protocol.  Initial versions of
	     resolvconf did not recommend a protocol tag be appended to the
	     interface name.  When the protocol is absent, it is assumed to be
	     the DHCP protocol.

     ppp     Point-to-Point Protocol.

     ra      IPv6 Router Advertisement.

     dhcp6   Dynamic Host Configuration Protocol, version 6.

IMPLEMENTATION NOTES
     If a subscriber has the executable bit then it is executed otherwise it
     is assumed to be a shell script and sourced into the current environment
     in a subshell.  This is done so that subscribers can remain fast, but are
     also not limited to the shell language.

     Portable subscribers should not use anything outside of /bin and /sbin
     because /usr and others may not be available when booting.  Also, it
     would be unwise to assume any shell specific features.

ENVIRONMENT
     IF_METRIC
     If the -m option is not present then we use IF_METRIC for the metric.

     IF_PRIVATE
     Marks the interface resolv.conf as private.

     IF_EXCLUSIVE
     Marks the interface resolv.conf as exclusive.

FILES
     /etc/resolv.conf.bak
     Backup file of the original resolv.conf.

     /etc/resolvconf.conf
     Configuration file for resolvconf.

     /libexec/resolvconf
     Directory of subscribers which are run every time resolvconf adds,
     deletes or updates.

     /libexec/resolvconf/libc.d
     Directory of subscribers which are run after the libc subscriber is run.

     /var/run/resolvconf
     State directory for resolvconf.

HISTORY
     This implementation of resolvconf is called openresolv and is fully com‐
     mand line compatible with Debian's resolvconf, as written by Thomas Hood.

SEE ALSO
     resolv.conf(5), resolvconf.conf(5), resolver(3), stdin(3)

AUTHORS
     Roy Marples ⟨roy@marples.name⟩

BUGS
     Please report them to
	   http://roy.marples.name/projects/openresolv

     resolvconf does not validate any of the files given to it.

     When running a local resolver other than libc, you will need to configure
     it to include files that resolvconf will generate.  You should consult
     resolvconf.conf(5) for instructions on how to configure your resolver.

BSD				April 27, 2014				   BSD