Dynamic DNS Service

Simple dynamic DNS service for A and AAAA records. The client updates the IP record for the specified domain.

Important: the api service must run behind a secure HTTPs proxy.

Server

Server Config

ttl: 2mkeys:
foo.sample.com: "RANDOM_60_CHAR_KEY_HERE"

Systemd Service Sample with Traefik Proxy

[Unit]Description=DynDNS Service
After=docker.service
Requires=docker.service
[Install]WantedBy=multi-user.target
[Service]TimeoutStartSec=0
Restart=always
ExecStartPre=-/usr/bin/docker kill ddns
ExecStartPre=-/usr/bin/docker rm ddns
ExecStartPre=-/usr/bin/docker pull desertbit/ddns
ExecStart=/usr/bin/docker run \
--name ddns \
-p 53:53/udp \
-p 53:53/tcp \
--label "traefik.enable=true" \
--label "traefik.http.routers.ddns.rule=Host(`ns.sample.com`)" \
--label "traefik.http.services.ddns.loadbalancer.server.port=80" \
--label "traefik.http.routers.ddns.entrypoints=websecure" \
-v /data/ddns:/data \
--network="http_network" \
desertbit/ddns server \
--conf /data/ddns.yaml \
--db /data/ddns.db
ExecStop=/usr/bin/docker stop ddns

Client

[Unit]Description=DynDNS Service
After=docker.service
Requires=docker.service
[Install]WantedBy=multi-user.target
[Service]TimeoutStartSec=0
Restart=always
ExecStartPre=-/usr/bin/docker kill ddns
ExecStartPre=-/usr/bin/docker rm ddns
ExecStartPre=-/usr/bin/docker pull desertbit/ddns
ExecStart=/usr/bin/docker run \
--name ddns \
desertbit/ddns client \
--url "https://ns.sample.com" \
--domain "foo.sample.com" \
--interval 1m \
--key "RANDOM_60_CHAR_KEY_HERE"ExecStop=/usr/bin/docker stop ddns

DNS Setup

Given your domain is sample.com, log in to your domain hoster and create a subdomain with a dedicated NS record that points to your newly created DNS. The NS record itself should point to a A record that is also created, which again points to the IP address of your DNS, like this:

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

SystemD ResolveD Port Issue

systemd-resolved uses port 53. Instead of disabling this service, remap incoming packets from wan to a new port. The docker container will listen on this new port. dstapp/docker-ddns#5

table ip router {
# Both need to be set even when one is empty.
chain prerouting {
type nat hook prerouting priority 0;
iifname $wan_iface udp dport 53 counter redirect to :55553
}
chain postrouting {
type nat hook postrouting priority 100;
}
}

Credits

• http://mkaczanowski.com/golang-build-dynamic-dns-service-go
• https://www.davd.io/build-your-own-dynamic-dns-in-5-minutes/
• https://github.com/muka/ddns
• https://serverfault.com/questions/804492/dns-servfail-at-some-of-nameservers/804526

License

MIT License