Dynamic DNS with Docker, Go and Bind9

This package allows you to set up a dynamic DNS server that allows you to connect to devices at home from anywhere in the world. All you need is a cheap VPS, a domain and access to it's nameserver.

Installation

You can either take the image from DockerHub or build it on your own.

Using DockerHub

Just customize this to your needs and run:

docker run -it -d \
    -p 8080:8080 \
    -p 53:53 \
    -p 53:53/udp \
    -e SHARED_SECRET=changeme \
    -e ZONE=example.org \
    -e RECORD_TTL=3600 \
    --name=dyndns \
    davd/docker-ddns:latest

If you want to persist DNS configuration across container recreation, add -v /somefolder:/var/cache/bind. If you are experiencing any issues updating DNS configuration using the API (NOTAUTH and SERVFAIL), make sure to add writing permissions for root (UID=0) to your persistent storage (e.g. chmod -R a+w /somefolder).

You can also use Compose / Swarm to set up this project. For more information and an example docker-compose.yml with persistent data storage, please refer to this file: https://github.com/dprandzioch/docker-ddns/blob/master/docker-compose.yml

Build from source / GitHub

git clone https://github.com/dprandzioch/docker-ddns
git checkout master # Make sure to build the latest stable release
cd docker-ddns
$EDITOR envfile
make deploy

Make sure to change all environment variables in envfile to match your needs. Some more information can be found here: https://www.davd.eu/build-your-own-dynamic-dns-in-5-minutes/

Exposed ports

Afterwards you have a running docker container that exposes three ports:

• 53/TCP -> DNS
• 53/UDP -> DNS
• 8080/TCP -> Management REST API

Using the API

That package features a simple REST API written in Go, that provides a simple interface, that almost any router that supports Custom DDNS providers can attach to (e.g. Fritz!Box). It is highly recommended to put a reverse proxy before the API.

It provides one single GET request, that is used as follows:

http://myhost.mydomain.tld:8080/update?secret=changeme&domain=foo&addr=1.2.3.4

Fields

• secret: The shared secret set in envfile
• domain: The subdomain to your configured domain, in this example it would result in foo.example.org. Could also be multiple domains that should be redirected to the same domain separated by comma, so "foo,bar"
• addr: IPv4 or IPv6 address of the name record

Accessing the REST API log

Just run

docker logs -f dyndns

DNS setup

To provide a little help... To your "real" domain, like domain.tld, you should add a subdomain that is delegated to this DDNS server like this:

dyndns                   IN NS      ns
ns                       IN A       <put ipv4 of dns server here>
ns                       IN AAAA    <optional, put ipv6 of dns server here>

Your management API should then also be accessible through

http://ns.domain.tld:8080/update?...

If you provide foo as a domain when using the REST API, the resulting domain will then be foo.dyndns.domain.tld.

Common pitfalls

• If you're on a systemd-based distribution, the process systemd-resolved might occupy the DNS port 53. Therefore starting the container might fail. To fix this disable the DNSStubListener by adding DNSStubListener=no to /etc/systemd/resolved.conf and restart the service using sudo systemctl restart systemd-resolved.service but be aware of the implications... Read more here: https://www.freedesktop.org/software/systemd/man/systemd-resolved.service.html and dstapp#5