Set custom DNS resolution for Docker

Alex Camilleri

Feb 13, 2025 • 1 min read

During a system migration it might happen that a new Docker installation could fail setting up custom DNS resolution when using pihole as a custom DNS server.

This can cause situations where services (ie NodeRed) fail to connect to other ones when using a custom domain (ie http://mydomain.com:8123), as opposed to IP:PORT.

To fix this, on a Raspberry Pi, find or create /etc/docker/daemon.json and add the following content:

{
  "dns": ["<DNS_IP>", "127.0.0.1"]
}

where DNS_IP should be the IP of the machine running pihole.

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