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 \fIyou\fR are responsible for re\-signing the zonefile\.
\fBtransfer\fR enables zone transfers\. It may be specified multiples times\.\fBTo\fR or \fBfrom\fR signals the direction\.\fBADDRESS\fR must be denoted in CIDR notation (e\.g\., 127\.0\.0\.1/32) or just as plain addresses\. The special wildcard \fB*\fR 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\.
\fBreload\fR interval to perform a reload of the zone if the SOA version changes\. Default is one minute\. Value of \fB0\fR means to not scan for changes and reload\. For example, \fB30s\fR checks the zonefile every 30 seconds and reloads the zone when serial changes\.
\fBupstream\fR 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 \fIor\fR want to use this\. CoreDNS will resolve CNAMEs against itself\.