* [kubernetes](https://coredns.io/plugins/kubernetes/): CoreDNS will reply to DNS queries
  based on IP of the Services and Pods. You can find [more details](https://coredns.io/plugins/kubernetes/)
  about this plugin on the CoreDNS website.
  - `ttl` allows you to set a custom TTL for responses. The default is 5 seconds.
    The minimum TTL allowed is 0 seconds, and the maximum is capped at 3600 seconds.
    Setting TTL to 0 will prevent records from being cached.  
  - The `pods insecure` option is provided for backward compatibility with `kube-dns`.
  - You can use the `pods verified` option, which returns an A record only if there exists a pod
    in the same namespace with a matching IP.
  - The `pods disabled` option can be used if you don't use pod records.
* [prometheus](https://coredns.io/plugins/metrics/): Metrics of CoreDNS are available at
  `http://localhost:9153/metrics` in the [Prometheus](https://prometheus.io/) format
  (also known as OpenMetrics).
* [forward](https://coredns.io/plugins/forward/): Any queries that are not within the Kubernetes
  cluster domain are forwarded to predefined resolvers (/etc/resolv.conf).
* [cache](https://coredns.io/plugins/cache/): This enables a frontend cache.
* [loop](https://coredns.io/plugins/loop/): Detects simple forwarding loops and
  halts the CoreDNS process if a loop is found.
* [reload](https://coredns.io/plugins/reload): Allows automatic reload of a changed Corefile.
  After you edit the ConfigMap configuration, allow two minutes for your changes to take effect.
* [loadbalance](https://coredns.io/plugins/loadbalance): This is a round-robin DNS loadbalancer
  that randomizes the order of A, AAAA, and MX records in the answer.

You can modify the default CoreDNS behavior by modifying the ConfigMap.

### Configuration of Stub-domain and upstream nameserver using CoreDNS

CoreDNS has the ability to configure stub-domains and upstream nameservers
using the [forward plugin](https://coredns.io/plugins/forward/).

#### Example

If a cluster operator has a [Consul](https://www.consul.io/) domain server located at "10.150.0.1",
and all Consul names have the suffix ".consul.local". To configure it in CoreDNS,
the cluster administrator creates the following stanza in the CoreDNS ConfigMap.

```
consul.local:53 {
    errors
    cache 30
    forward . 10.150.0.1
}
```

To explicitly force all non-cluster DNS lookups to go through a specific nameserver at 172.16.0.1,
point the `forward` to the nameserver instead of `/etc/resolv.conf`

```
forward .  172.16.0.1
```

The final ConfigMap along with the default `Corefile` configuration looks like:

```yaml
apiVersion: v1
kind: ConfigMap
metadata:
  name: coredns
  namespace: kube-system
data:
  Corefile: |
    .:53 {
        errors
        health
        kubernetes cluster.local in-addr.arpa ip6.arpa {
           pods insecure
           fallthrough in-addr.arpa ip6.arpa
        }
        prometheus :9153
        forward . 172.16.0.1
        cache 30
        loop
        reload
        loadbalance
    }
    consul.local:53 {
        errors
        cache 30
        forward . 10.150.0.1
    }
```

{{< note >}}
CoreDNS does not support FQDNs for stub-domains and nameservers (eg: "ns.foo.com").
During translation, all FQDN nameservers will be omitted from the CoreDNS config.
{{< /note >}}

## {{% heading "whatsnext" %}}

- Read [Debugging DNS Resolution](/docs/tasks/administer-cluster/dns-debugging-resolution/)