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CoreDNS plugin for replacing CNAME records on zone apex

Home Page: https://coredns.io/explugins/alias/

License: Apache License 2.0

Go 89.33% DIGITAL Command Language 4.86% Makefile 5.81%

aname coredns coredns-plugin golang

alias's Introduction

alias

The alias plugin eliminates CNAME records from zone apex by making the subsequent resolved records look like they belong to the zone apex. This behaves similarily to CloudFlare's Zone Flattening.

This plugin works only with plugins that produce A or AAAA records alongside the CNAME record. Examples include auto and file. However, you might need to adjust the order of this plugin to use it with other plugins.

Preferrably, this should not be used in favour of the RFC drafts for the new ANAME records, but the DNS library used by CoreDNS does not support ANAME records yet.

Release builds can be found here

Syntax

alias

Examples

example.com {
	file db.example.com
	alias
}
# This is used to resolve CNAME records by the `file` plugin. Modify accordingly
. {
	forward . 1.1.1.1 1.0.0.1
}

This will transform responses like this:

;; ANSWER SECTION:
example.com.		3600	IN	CNAME	two.example.org.
two.example.org.	3600	IN	CNAME	one.example.net.
one.example.net.	3600	IN	A	127.0.0.1

into

;; ANSWER SECTION:
example.com.		3600	IN	A	127.0.0.1

See example/ for a more extensive example.

Installation

As per CoreDNS docs, there are two ways.

Build with compile-time configuration file

$ git clone https://github.com/coredns/coredns
$ cd coredns
$ vim plugin.cfg
# Add the line alias:github.com/serverwentdown/alias before the file middleware
$ go generate
$ go build
$ ./coredns -plugins | grep alias

Build with external golang source code

$ git clone https://github.com/serverwentdown/alias
$ cd alias/coredns
$ go build
$ ./coredns -plugins | grep alias

alias's People

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johnjones section-io hennemon ericogr themisir jremerich cagriekin kokizzu guarandoo

alias's Issues

Doesn't work with MX record.

if we set CNAME to zone apex.
coredns returns only CNAME record with MX query.

example.com.	300	IN	MX	mx.example.org.
example.com.	300	IN	CNAME	some.magic.example.org.
some.magic.example.org. 300 IN A	123.123.45.67

$ dig example.org mx

;; ANSWER SECTION:
example.org.                300      IN      CNAME   some.magic.example.org.

Your plugin just remove the CNAME, so we get empty response. :-(

Does alias supposed to rewrite CNAMEs for external domains too?

Let's say I have the following dns file:

example.org. 3600 IN CNAME twitter.org.

And I have alias and forward plugins enabled:

. {
  log
  forward . 1.1.1.1 1.0.0.1
}

example.org {
  file db.example.org
  alias
}

When I dig example.org, I see that DNS response contains both CNAME and A records (resolved from twitter.com). Is it possible to remove CNAME records and just respond resolved A records?

I'm new to CoreDNS stuff, so sorry if I misunderstood something.

update for coredns master

We've renamed middleware to plugin to have more consitant naming and keep in sync with caddy.

For the example plugin, this diff we needed; it is just renaming middleware to plugin:
see coredns/example@fe5e8f0

Compiling 1.8.0 breaks building when using this plugin

When I add this plugin and try to compile coredns I get the following error:

#8 92.73 go: github.com/coredns/coredns imports
#8 92.73 	github.com/coredns/coredns/core/plugin imports
#8 92.73 	github.com/jiachengxu/idetcd imports
#8 92.73 	github.com/mholt/caddy/onevent: github.com/mholt/[email protected]: parsing go.mod:
#8 92.73 	module declares its path as: github.com/caddyserver/caddy
#8 92.73 	        but was required as: github.com/mholt/caddy

The 1.8.0 coredns logs mention this in their release notes:

Caddy is now developing a version 2 and we are using version 1, we've internalized
Caddy into <https://github.com/coredns/caddy>. This means the `caddy` types change and *all* plugins
need to fix the import path from: `github.com/caddyserver/caddy` to `github.com/coredns/caddy` (this
can thankfully be automated).

Does not work (or I don't understand how to use it)

I have the following config:

// Corefile
spiral.sh {
	file zones/spiral.sh
	alias
}

; zone
http-pool.spiral.sh. 3000 IN A 128.116.205.8
http-pool.spiral.sh. 3000 IN A 45.61.184.138
spiral.sh. 3000 IN CNAME http-pool.spiral.sh.

dig output:

;; ANSWER SECTION:
spiral.sh.		3000	IN	CNAME	http-pool.spiral.sh.
http-pool.spiral.sh.	3000	IN	A	128.116.205.8
http-pool.spiral.sh.	3000	IN	A	45.61.184.138

What am I doing wrong? I would like to show just the A records and not the CNAME, as shown in the example on the README.