coredns/middleware/file

file

file enables serving zone data from an RFC 1035-style master file.

The file middleware 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. DNSSEC) correct DNSSEC answers are returned. Only NSEC is supported! If you use this setup you are responsible for resigning the zonefile.

Syntax

file DBFILE [ZONES...]

• DBFILE the database file to read and parse. If the path is relative the path from the root directive 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 middleware.

TSIG key configuration is TODO; directive format for transfer will probably be extended with TSIG key information, something like transfer out [ADDRESS...] key [NAME[:ALG]] [BASE64]

file DBFILE [ZONES... ] {
    transfer to ADDRESS...
    no_reload
    upstream ADDRESS...
}

• transfer enables zone transfers. It may be specified multiples times. To or from signals the direction. ADDRESS must be denoted in CIDR notation (127.0.0.1/32 etc.) 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.
• no_reload by default CoreDNS will reload a zone from disk whenever it detects a change to the file. This option disables that behavior.
• upstream defines upstream resolvers to be used resolve external names found (think CNAMEs) pointing to external names. This is only really useful when CoreDNS is configured as a proxy, for normal authoritative serving you don't need or want to use this.

Examples

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

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