Mirror of CoreDNS, a fast and flexible DNS server.
You can not select more than 25 topics Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
Nguyen Hai Truong 9ce9308f5c Trivial fix typo (#2590) 11 hours ago
.github Add CONTRIBUTING symlink (#2540) 1 week ago
.presubmit Add presubmit to check if there are any files that have `import "testing"` (#2480) 1 month ago
core Remove some duplicate worlds (#2582) 1 day ago
coremain Tag version 1.3.1 (#2458) 1 month ago
man Generate man-pages (#2439) 1 month ago
pb Remove grpc watch functionality (#2549) 1 week ago
plugin Trivial fix typo (#2590) 11 hours ago
request Fix some typos (#2560) 4 days ago
test Fix a flaky test by not depending on Google (#2565) 4 days ago
vendor Replacing 'HTTP' by 'HTTPS' for securing links (#2591) 11 hours ago
.benchmark.sh benchmark are spammy (#2144) 4 months ago
.codecov.yml Increase codecov target requirement to 50% (from 40%) (#1344) 1 year ago
.dockerignore dockerignore: ignore .git (#1723) 10 months ago
.gitignore Add debug.Hexdump (#1902) 7 months ago
.stickler.yml Add stickler config (#2009) 6 months ago
.travis.yml Remove benchmark from travis (#2350) 2 months ago
ADOPTERS.md Correct misspelling of Kubernetes (#2579) 2 days ago
CODE-OF-CONDUCT.md Change http to https for security links (#2559) 6 days ago
CONTRIBUTING.md Change http to https for security links (#2559) 6 days ago
Dockerfile Docker: drop alpine (#1843) 8 months ago
GOVERNANCE.md Governance: Clarify definition of "Transparent and accessible" (#2300) 3 months ago
Gopkg.lock Remove version pinning of thrift, ugoriji/go, and etcd (#2457) 1 month ago
Gopkg.toml Remove version pinning of thrift, ugoriji/go, and etcd (#2457) 1 month ago
LICENSE Cleanups, removing Caddy name a bit more 2 years ago
Makefile Upgrade caddy to 0.11.X (#2541) 4 days ago
Makefile.doc Run make -f Makefile.doc (#1875) 8 months ago
Makefile.fuzz Fuzzing: add more fuzzing targets (#2402) 2 months ago
Makefile.release rename VERBOSE to be more generic (#2172) 4 months ago
OWNERS OWNERS: Add email (#2313) 3 months ago
README.md Fix some typos in documents (#2592) 11 hours ago
SECURITY-RELEASE-PROCESS.md Update SECURITY-RELEASE-PROCESS.md (#2237) 3 months ago
coredns.1.md Run make -f Makefile.doc (#1875) 8 months ago
coredns.go Enhancement of external plugin enabling (#1392) 1 year ago
corefile.5.md Add import plugin to give it docs (#2428) 1 month ago
directives_generate.go Enhancement of external plugin enabling (#1392) 1 year ago
plugin.cfg Add new plugin: external - resolve k8s ingress and LB address with external names (#2379) 2 months ago
plugin.md Fix some typos in comment (#2520) 2 weeks ago

README.md

CoreDNS

Documentation Build Status Code Coverage Docker Pulls Go Report Card CII Best Practices

CoreDNS (written in Go) chains plugins. Each plugin performs a DNS function.

CoreDNS is a Cloud Native Computing Foundation graduated project.

CoreDNS is a fast and flexible DNS server. The keyword here is flexible: with CoreDNS you are able to do what you want with your DNS data by utilizing plugins. If some functionality is not provided out of the box you can add it by writing a plugin.

CoreDNS can listen for DNS requests coming in over UDP/TCP (go’old DNS), TLS (RFC 7858) and gRPC (not a standard).

Currently CoreDNS is able to:

  • Serve zone data from a file; both DNSSEC (NSEC only) and DNS are supported (file and auto).
  • Retrieve zone data from primaries, i.e., act as a secondary server (AXFR only) (secondary).
  • Sign zone data on-the-fly (dnssec).
  • Load balancing of responses (loadbalance).
  • Allow for zone transfers, i.e., act as a primary server (file).
  • Automatically load zone files from disk (auto).
  • Caching (cache).
  • Use etcd as a backend (replace SkyDNS) (etcd).
  • Use k8s (kubernetes) as a backend (kubernetes).
  • Serve as a proxy to forward queries to some other (recursive) nameserver (forward).
  • Provide metrics (by using Prometheus) (metrics).
  • Provide query (log) and error (errors) logging.
  • Support the CH class: version.bind and friends (chaos).
  • Support the RFC 5001 DNS name server identifier (NSID) option (nsid).
  • Profiling support (pprof).
  • Rewrite queries (qtype, qclass and qname) (rewrite and template).

And more. Each of the plugins is documented. See coredns.io/plugins for all in-tree plugins, and coredns.io/explugins for all out-of-tree plugins.

Compilation from Source

To compile CoreDNS, we assume you have a working Go setup. See various tutorials if you don’t have that already configured.

First, make sure your $GOPATH is correctly set. See here for details. Then, check out the project under your $GOPATH and run make to compile the binary:

$ mkdir -p $GOPATH/src/github.com/coredns
$ cd $GOPATH/src/github.com/coredns/
$ git clone https://github.com/coredns/coredns
$ cd coredns
$ make

This should yield a coredns binary.

We vendor most (not all!) packages. This is mostly because vendoring isn’t a perfect solution (in Go). We don’t vendor mholt/caddy and miekg/dns for instance. Using make will pull down these dependencies and checks out the correct version as well.

Compilation with Docker

CoreDNS requires Go to compile. However, if you already have docker installed and prefer not to setup a Go environment, you could build CoreDNS easily:

$ docker run --rm -i -t -v $PWD:/go/src/github.com/coredns/coredns \
      -w /go/src/github.com/coredns/coredns golang:1.11 make

The above command alone will have coredns binary generated.

Examples

When starting CoreDNS without any configuration, it loads the whoami plugin and starts listening on port 53 (override with -dns.port), it should show the following:

.:53
2016/09/18 09:20:50 [INFO] CoreDNS-001
CoreDNS-001

Any query sent to port 53 should return some information; your sending address, port and protocol used.

If you have a Corefile without a port number specified it will, by default, use port 53, but you can override the port with the -dns.port flag:

./coredns -dns.port 1053, runs the server on port 1053.

Start a simple proxy. You’ll need to be root to start listening on port 53.

Corefile contains:

.:53 {
    forward . 8.8.8.8:53
    log
}

Just start CoreDNS: ./coredns. Then just query on that port (53). The query should be forwarded to 8.8.8.8 and the response will be returned. Each query should also show up in the log which is printed on standard output.

Serve the (NSEC) DNSSEC-signed example.org on port 1053, with errors and logging sent to standard output. Allow zone transfers to everybody, but specifically mention 1 IP address so that CoreDNS can send notifies to it.

example.org:1053 {
    file /var/lib/coredns/example.org.signed {
        transfer to *
        transfer to 2001:500:8f::53
    }
    errors
    log
}

Serve example.org on port 1053, but forward everything that does not match example.org to a recursive nameserver and rewrite ANY queries to HINFO.

.:1053 {
    rewrite ANY HINFO
    forward . 8.8.8.8:53

    file /var/lib/coredns/example.org.signed example.org {
        transfer to *
        transfer to 2001:500:8f::53
    }
    errors
    log
}

IP addresses are also allowed. They are automatically converted to reverse zones:

10.0.0.0/24 {
    whoami
}

Means you are authoritative for 0.0.10.in-addr.arpa..

This also works for IPv6 addresses. If for some reason you want to serve a zone named 10.0.0.0/24 add the closing dot: 10.0.0.0/24. as this also stops the conversion.

This even works for CIDR (See RFC 1518 and 1519) addressing, i.e. 10.0.0.0/25, CoreDNS will then check if the in-addr request falls in the correct range.

Listening on TLS and for gRPC? Use:

tls://example.org grpc://example.org {
    whoami
}

Specifying ports works in the same way:

grpc://example.org:1443 {
    # ...
}

When no transport protocol is specified the default dns:// is assumed.

Community

We’re most active on Github (and Slack):

More resources can be found:

Deployment

Examples for deployment via systemd and other use cases can be found in the deployment repository.

Deprecation Policy

When there is a backwards incompatible change in CoreDNS the following process is followed:

  • Release x.y.z: Announce that in the next release we will make backward incompatible changes.
  • Release x.y+1.0: Increase the minor version and set the patch version to 0. Make the changes, but allow the old configuration to be parsed. I.e. CoreDNS will start from an unchanged Corefile.
  • Release x.y+1.1: Increase the patch version to 1. Remove the lenient parsing, so CoreDNS will not start if those features are still used.

E.g. 1.3.1 announce a change. 1.4.0 a new release with the change but backward compatible config. And finally 1.4.1 that removes the config workarounds.

Security

Security Audit

A third party security audit was performed by Cure53, you can see the full report here.

Reporting security vulnerabilities

If you find a security vulnerability or any security related issues, please DO NOT file a public issue, instead send your report privately to security@coredns.io. Security reports are greatly appreciated and we will publicly thank you for it.

Please consult security vulnerability disclosures and security fix and release process document