--- name: "resolvconf" section: "8" platform: "linux" package: "openresolv" version: "3.17.4-1" release: "Arch Linux 2026-11-01" platforms: ["linux", "freebsd"] url: "https://new.carta.tech/resolvconf/8" --- # resolvconf(8) a framework for managing multiple DNS configurations ## NAME **resolvconf** – a framework for managing multiple DNS configurations ## SYNOPSIS **resolvconf** **-I** **resolvconf** \[**-m** *metric*\] \[**-p**\] \[**-x**\] **-a** *key* \<*file* **resolvconf** **-C** *pattern* **resolvconf** **-c** *pattern* **resolvconf** \[**-f**\] **-d** *key* **resolvconf** \[**-x**\] **-iLlp** *pattern* **resolvconf** **-u** **resolvconf** **-****-version** ## DESCRIPTION **resolvconf** manages [resolv.conf(5)](/resolv.conf/5.md) 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)](/resolv.conf/5.md) file to **resolvconf** via [stdin(4)](/stdin/4.md) with the argument **-a** *key* instead of the filesystem. **resolvconf** then updates */etc/resolv.conf* as it thinks best. If */etc/resolv.conf* already exists and the top line does not match the expected signature, then **resolvconf** will refuse to update it unless the **-u** update command is given. When a local resolver other than libc is installed, such as [dnsmasq(8)](/dnsmasq/8.md) or [named(8)](/named/8.md), then **resolvconf** will supply files that the resolver should be configured to include. At it's heart, **resolvconf** is a key/value store for *resolv.conf* files. Each entry must have a unique *key* and should be expressed as **interface.protocol** so that it's easy to tell from where the *resolv.conf* file came from. This also allows using pattern matching such as **interface.\*** to match all protocols running on the interface. For example, a modern system will likely run DHCP, RA and DHCPv6 which could be from separate programs or one program running many protocols. However, this is not a fixed requirement, **resolvconf** will work with any key name and it should be treated as an opaque value outside of **resolvconf**. **resolvconf** can mark a *resolv.conf* as private and optionally non-searchable. 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 and if non-searchable then the domain/search listed are excluded from the global search list defined in */etc/resolv.conf*. This only works when a local resolver other than libc is installed. See [resolvconf.conf(5)](/resolvconf.conf/5.md) for how to configure **resolvconf** to use a local name server and how to remove the private marking. **resolvconf** can mark a *resolv.conf* as exclusive. Only the latest exclusive key is used for processing, otherwise all are. When a configuration source goes away, such as an interface going down or a VPN stopping, it should then call **resolvconf** with **-d** *key* arguments to clean up the *resolv.conf* it added previously. For systems that support the concept of persisting configuration when the source is suspended, such as the carrier going down, then it should instead call **resolvconf** with **-C** *key* arguments to deprecate the entry **-c** *key* to activate the entry when it comes back again. This only affects the order in which the *resolv.conf* entries are processed. Here are some options for the above commands: - **-f** Ignore non existent *resolv.conf* entries. Only really useful for deleting. - **-m** *metric* Set the metric of the *resolv.conf* entry when adding it, default of 0. Lower metrics take precedence. This affects the default order of entires when listed. - **-p** \[*pattern*\] Marks the *resolv.conf* as private if the **-a** command is given, otherwise *resolv.conf* entries having their key matching *pattern* are listed. If an extra **-p** is given then the *resolv.conf* is marked as non-searchable as well. - **-x** Mark the *resolv.conf* as exclusive when adding, otherwise only use the latest exclusive key. **resolvconf** has some more commands for general usage: - **-i** \[*pattern*\] List the keys stored, optionally matching *pattern*, we have *resolv.conf* files for. If the **-L** option is given first, then the keys will be list post-processed. - **-L** \[*pattern*\] List the *resolv.conf* files we have, post-processed by the [resolvconf.conf(5)](/resolvconf.conf/5.md) configuration. If *pattern* is specified then we list the files for the keys which match it. - **-l** \[*pattern*\] List the *resolv.conf* files we have. If *pattern* is specified then we list the files for the keys which match it. that match it. - **-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 key. - **-****-version** Echo the resolvconf version to *stdout*. **resolvconf** also has some commands designed to be used by its subscribers and system startup: - **-I** Initialise the state directory */run/resolvconf*. This should be called after the base state directory has either been cleaned out or mounted as a memory backed filesystem during the initial boot sequence before any daemon has the chance to call **resolvconf**. - **-R** Echo the command used to restart a service. - **-r** *service* If the *service* is running then restart it. If the service does not exist or is not running then zero is returned, otherwise the result of restarting the service. - **-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)](/resolvconf.conf/5.md) is set. ## RESOLV.CONF ORDERING For **resolvconf** to work effectively, it has to process the *resolv.conf* entries in the correct order. **resolvconf** first processes keys from the **key\_order** list, then entries without a metric and that match the **dynamic\_order** list, then entries with a metric in order and finally the rest in the operating systems lexical order. See [resolvconf.conf(5)](/resolvconf.conf/5.md) for details on these lists. ## PROTOCOLS Here are some suggested protocol tags to use for each *resolv.conf* - dhcp Dynamic Host Configuration 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 *resolv.conf* as private. - *IF\_NOSEARCH* Marks the *resolv.conf* as non-searchable. - *IF\_EXCLUSIVE* Marks the *resolv.conf* as exclusive. ## FILES - */etc/resolv.conf.bak* Backup file of the original resolv.conf. - */etc/resolvconf.conf* Configuration file for **resolvconf**. - */usr/lib/resolvconf* Directory of subscribers which are run every time **resolvconf** adds, deletes or updates. - */usr/lib/resolvconf/libc.d* Directory of subscribers which are run after the libc subscriber is run. - */run/resolvconf* State directory for **resolvconf**. ## NOTES Domain labels are assumed to be in ASCII and are converted to lower case to avoid duplicate zones when given differing case from different sources. 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)](/resolvconf.conf/5.md) for instructions on how to configure your resolver. ## SEE ALSO [resolver(3)](/resolver/3.md), [stdin(4)](/stdin/4.md), [resolv.conf(5)](/resolv.conf/5.md), [resolvconf.conf(5)](/resolvconf.conf/5.md) ## HISTORY This implementation of **resolvconf** is called openresolv and is fully command line compatible with Debian's resolvconf, as written by Thomas Hood. ## AUTHORS Roy Marples ⟨*roy@marples.name*⟩ ## BUGS Please report them to **http://roy.marples.name/projects/openresolv**