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141 lines
3.3 KiB
Markdown
141 lines
3.3 KiB
Markdown
## Name
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*corefile* - configuration file for CoreDNS.
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## Description
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A *corefile* specifies the internal servers CoreDNS should run and what plugins each of these
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should chain. The syntax is as follows:
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~~~ txt
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[SCHEME://]ZONE [[SCHEME://]ZONE]...[:PORT] {
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[PLUGIN]...
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}
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~~~
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The **ZONE** defines for which name this server should be called, multiple zones are allowed and
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should be *white space* separated. You can use a "reverse" syntax to specify a reverse zone (i.e.
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ip6.arpa and in-addr.arpa), by using an IP address in the CIDR notation.
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The optional **SCHEME** defaults to `dns://`, but can also be `tls://` (DNS over TLS), `grpc://`
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(DNS over gRPC) or `https://` (DNS over HTTP/2).
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The optional **PORT** controls on which port the server will bind, this default to 53. If you use
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a port number here, you *can't* override it with `-dns.port` (coredns(1)), also see coredns-bind(7).
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Specifying a **ZONE** *and* **PORT** combination multiple times for *different* servers will lead to
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an error on startup.
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When a query comes in, it is matched again all zones for all servers, the server with the longest
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match on the query name will receive the query.
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**PLUGIN** defines the plugin(s) we want to load into this server. This is optional as well, but as
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server with no plugins will just return SERVFAIL for all queries. Each plugin can have a number of
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properties than can have arguments, see the documentation for each plugin.
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Comments are allowed and begin with an unquoted hash `#` and continue to the end of the line.
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Comments may be started anywhere on a line.
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Environment variables are supported and either the Unix or Windows form may be used: `{$ENV_VAR_1}`
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or `{%ENV_VAR_2%}`.
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You can use the `import` "plugin" (See coredns-import(7)) to include parts of other files.
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If CoreDNS can’t find a Corefile to load it loads the following builtin one:
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~~~ corefile
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. {
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whoami
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log
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}
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~~~
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## Import
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You can use the `import` "plugin" to include parts of other files, see
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<https://coredns.io/plugins/import>, and coredns-import(7).
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## Snippets
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If you want to reuse a snippet you can define one with and then use it with *import*.
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~~~ corefile
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(mysnippet) {
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log
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whoami
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}
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. {
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import mysnippet
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}
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~~~
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## Examples
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The **ZONE** is root zone `.`, the **PLUGIN** is *chaos*. The *chaos* plugin takes an (optional) argument:
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`CoreDNS-001`. This text is returned on a CH class query: `dig CH TXT version.bind @localhost`.
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~~~ corefile
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. {
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chaos CoreDNS-001
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}
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~~~
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When defining a new zone, you either create a new server, or add it to an existing one. Here we
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define one server that handles two zones; that potentially chain different plugins:
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~~~ corefile
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example.org {
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whoami
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}
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org {
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whoami
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}
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~~~
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Is identical to:
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~~~ corefile
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example.org org {
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whoami
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}
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~~~
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Reverse zones can be specified as domain names:
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~~~ corefile
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0.0.10.in-addr.arpa {
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whoami
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}
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~~~
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or by just using the CIDR notation:
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~~~ corefile
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10.0.0.0/24 {
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whoami
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}
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~~~
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This also works on a non octet boundary:
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~~~ corefile
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10.0.0.0/27 {
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whoami
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}
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~~~
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## Authors
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CoreDNS Authors.
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## Copyright
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Apache License 2.0
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## See Also
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The manual page for CoreDNS: coredns(1) and more documentation on <https://coredns.io>.
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Also see the [*import*](https://coredns.io/plugins/import)'s documentation and all the manual pages
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for the plugins.
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