coredns.io/content/plugins/secondary.md

+++ title = "secondary" description = "secondary enables serving a zone retrieved from a primary server." weight = 25 tags = [ "plugin", "secondary" ] categories = [ "plugin" ] date = "2017-09-15T21:22:42.286056" +++

Syntax

secondary [ZONES...]

• ZONES zones it should be authoritative for. If empty, the zones from the configuration block are used. Note that without a remote address to get the zone from, the above is not that useful.

A working syntax would be:

secondary [zones...] {
    transfer from ADDRESS
    transfer to ADDRESS
    upstream ADDRESS...
}

• transfer from specifies from which address to fetch the zone. It can be specified multiple times; if one does not work, another will be tried.
• transfer to can be enabled to allow this secondary zone to be transferred again.
• 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. ADDRESS can be an IP address, and IP:port or a string pointing to a file that is structured as /etc/resolv.conf.

Examples

Transfer example.org from 10.0.1.1, and if that fails try 10.1.2.1.

example.org {
    secondary {
        transfer from 10.0.1.1
        transfer from 10.1.2.1
    }
}

Or re-export the retrieved zone to other secondaries.

. {
    secondary example.net {
        transfer from 10.1.2.1
        transfer to *
    }
}