Files
coredns/plugin/acl
Miek Gieben 004c5fca9d all: simply registering plugins (#3287)
Abstract the caddy call and make it simpler.

See #3261 for some part of the discussion.

Go from:

~~~ go
func init() {
       caddy.RegisterPlugin("any", caddy.Plugin{
               ServerType: "dns",
               Action:     setup,
       })
}
~~~

To:

~~~ go
func init() { plugin.Register("any", setup) }
~~~

This requires some external documents in coredns.io to be updated as
well; the old way still works, so it's backwards compatible.

Signed-off-by: Miek Gieben <miek@miek.nl>
2019-09-20 08:02:30 +01:00
..
2019-09-04 19:06:10 -07:00

acl

acl - enforces access control policies on source ip and prevents unauthorized access to DNS servers.

Description

With acl enabled, users are able to block suspicous DNS queries by configuring IP filter rule sets, i.e. allowing authorized queries to recurse or blocking unauthorized queries.

This plugin can be used multiple times per Server Block.

Syntax

acl [ZONES...] {
    ACTION [type QTYPE...] [net SOURCE...]
}
  • ZONES zones it should be authoritative for. If empty, the zones from the configuration block are used.
  • ACTION (allow or block) defines the way to deal with DNS queries matched by this rule. The default action is allow, which means a DNS query not matched by any rules will be allowed to recurse.
  • QTYPE is the query type to match for the requests to be allowed or blocked. Common resource record types are supported. * stands for all record types. The default behavior for an omitted type QTYPE... is to match all kinds of DNS queries (same as type *).
  • SOURCE is the source IP address to match for the requests to be allowed or blocked. Typical CIDR notation and single IP address are supported. * stands for all possible source IP addresses.

Examples

To demonstrate the usage of plugin acl, here we provide some typical examples.

Block all DNS queries with record type A from 192.168.0.0/16

. {
    acl {
        block type A net 192.168.0.0/16
    }
}

Block all DNS queries from 192.168.0.0/16 except for 192.168.1.0/24:

. {
    acl {
        allow net 192.168.1.0/24
        block net 192.168.0.0/16
    }
}

Allow only DNS queries from 192.168.0.0/24 and 192.168.1.0/24:

. {
    acl {
        allow net 192.168.0.0/16 192.168.1.0/24
        block
    }
}

Block all DNS queries from 192.168.1.0/24 towards a.example.org:

example.org {
    acl a.example.org {
        block net 192.168.1.0/24
    }
}