auto

auto enables serving zone data from an RFC 1035-style master file, which is automatically picked up from disk.

Description

The auto plugin is used for an “old-style” DNS server. It serves from a preloaded file that exists on disk. If the zone file contains signatures (i.e. is signed, i.e. using DNSSEC) correct DNSSEC answers are returned. Only NSEC is supported! If you use this setup you are responsible for re-signing the zonefile. New or changed zones are automatically picked up from disk.

Syntax

auto [ZONES...] {
    directory DIR [REGEXP ORIGIN_TEMPLATE]
    transfer to ADDRESS...
    reload DURATION
}

ZONES zones it should be authoritative for. If empty, the zones from the configuration block are used.

  • directory loads zones from the specified DIR. If a file name matches REGEXP it will be used to extract the origin. ORIGIN_TEMPLATE will be used as a template for the origin. Strings like {<number>} are replaced with the respective matches in the file name, e.g. {1} is the first match, {2} is the second. The default is: db\.(.*) {1} i.e. from a file with the name db.example.com, the extracted origin will be example.com.
  • transfer enables zone transfers. It may be specified multiples times. To or from signals the direction. ADDRESS must be denoted in CIDR notation (e.g., 127.0.0.132) or just as plain addresses. The special wildcard * means: the entire internet (only valid for ‘transfer to’). When an address is specified a notify message will be send whenever the zone is reloaded.
  • reload interval to perform reloads of zones if SOA version changes and zonefiles. It specifies how often CoreDNS should scan the directory to watch for file removal and addition. Default is one minute. Value of 0 means to not scan for changes and reload. eg. 30s checks zonefile every 30 seconds and reloads zone when serial changes.

All directives from the file plugin are supported. Note that auto will load all zones found, even though the directive might only receive queries for a specific zone. I.e:

. {
    auto example.org {
        directory /etc/coredns/zones
    }
}

Will happily pick up a zone for example.COM, except it will never be queried, because the auto directive only is authoritative for example.ORG.

Examples

Load org domains from /etc/coredns/zones/org and allow transfers to the internet, but send notifies to 10.240.1.1

org {
    auto {
        directory /etc/coredns/zones/org
        transfer to *
        transfer to 10.240.1.1
    }
}

Load org domains from /etc/coredns/zones/org and looks for file names as www.db.example.org, where example.org is the origin. Scan every 45 seconds.

org {
    auto {
        directory /etc/coredns/zones/org www\.db\.(.*) {1}
        reload 45s
    }
}