RESOLVCONF(8) FreeBSD 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,
otherwise 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
subscriber 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
command 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 <
[email protected]>
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.
FreeBSD 14.1-RELEASE-p8 April 27, 2015 FreeBSD 14.1-RELEASE-p8