openresolv

openresolv is a resolvconf implementation, i.e. a resolv.conf management framework.

Although openresolv is most known for allowing multiple applications to modify /etc/resolv.conf, it is currently the only standard way to implement:

dynamic control of a DNS resolver (other than glibc),
dynamic conditional forwarding.

Tip: An alternative implementation is systemd-resolvconf, but it can only be used with systemd-resolved.

Installation

Install the openresolv package.

Usage

openresolv provides resolvconf(8) and is configured in /etc/resolvconf.conf. See resolvconf.conf(5) for supported options.

Running resolvconf -u will generate /etc/resolv.conf.

This article or section needs expansion.

Reason: Provide common usage examples. (Discuss in Talk:Openresolv)

Users

DHCP clients:

dhcpcd has a hook which uses resolvconf if it is installed.
iwd#Enable built-in network configuration

Network managers:

netctl (used by default)
NetworkManager#Use openresolv (limited to a single interface)

VPN clients:

Subscribers

openresolv can be configured to pass name servers and search domains to DNS resolvers. The supported resolvers are:

See the official documentation for instructions.

Tips and tricks

Defining multiple values for options

The man page does not mention it, but to define multiple values, for options that support it (e.g. name_servers, resolv_conf_options etc.) in /etc/resolvconf.conf, you need to write them space separated inside quotes. E.g.:

/etc/resolvconf.conf

resolv_conf_options="edns0 single-request"
name_servers="192.168.35.1 fd7b:d0bd:7a6e::1"