charlesportwoodii/coredns-partial

Partial - Semi Authoritative Zone Files for CoreDNS - A stand-in replacement for CoreDNS' file plugin with fallthrough support

file

Name

file - enables serving zone data from an RFC 1035-style master file with semi-authoritative options.

Description

The file 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 using DNSSEC), correct DNSSEC answers are returned. Only NSEC is supported! If you use this setup you are responsible for re-signing the zonefile.

Additionally, this modified plugin supports a semi-authoritative mode, where results not known by the nameserver are forwarded to the next chain, allowing for a horizon view if the record is not locally known for a particular record in a given zone.

Syntax

file DBFILE [ZONES...]

• DBFILE the database file to read and parse. If the path is relative, the path from the root plugin will be prepended to it.
• ZONES zones it should be authoritative for. If empty, the zones from the configuration block are used.

If you want to round-robin A and AAAA responses look at the loadbalance plugin.

file DBFILE [ZONES... ] {
    reload DURATION
    fallthrough
}

• reload interval to perform a reload of the zone if the SOA version changes. Default is one minute. Value of 0 means to not scan for changes and reload. For example, 30s checks the zonefile every 30 seconds and reloads the zone when serial changes.
• fallthrough, if specified will allow NXDOMAIN and other failures to be forwarded to the next plugin chain.

If you need outgoing zone transfers, take a look at the transfer plugin.

Examples

Load the example.org zone from example.org.signed and allow transfers to the internet, but send notifies to 10.240.1.1

example.org {
    file example.org.signed
    transfer {
        to * 10.240.1.1
    }
}

Or use a single zone file for multiple zones:

. {
    file example.org.signed example.org example.net
    transfer example.org example.net {
        to * 10.240.1.1
    }
}

Note that if you have a configuration like the following you may run into a problem of the origin not being correctly recognized:

. {
    file db.example.org
}

We omit the origin for the file db.example.org, so this references the zone in the server block, which, in this case, is the root zone. Any contents of db.example.org will then read with that origin set; this may or may not do what you want. It's better to be explicit here and specify the correct origin. This can be done in two ways:

. {
    file db.example.org example.org
}

Or

example.org {
    file db.example.org
}

See Also

See the loadbalance plugin if you need simple record shuffling. And the transfer plugin for zone transfers. Lastly the root plugin can help you specificy the location of the zone files.