Using DynDNS domain instead of IP

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1. The problem I’m having:

I’m trying to set up my own NextCloud AIO on my home server and using Caddy as reverse proxy.

  • I have the DynDNS domain name from my router (tp-link).
  • I have Wireguard VPN set up with my home server as client and the router is my VPN server.
  • I have my own domain and would like to use a subdomain (like nextcloud.mydomain.com) as I already have another server with different IP pointing to the main base domain.
  • I’ve opened the two ports Caddy’s documentation say to port-forward in my router. It gives me the option to choose to which device so they only access my server through the VPN

Currently I have my subdomain A record pointing to the endpoint of my VPN client on the home server, but that doesn’t seem to be it.

2. Error messages and/or full log output:

Yesterday when I ran docker compose up Caddy said it couldn’t find valid A records. Today (without me having changed anything other than restarting my server) it’s saying connection refused, it seems to be trying to read the local host IP..

"level":"error", "ts":1794347032.643504", "logger":"tls.obtain","msg":"will retry","error":"[``mysubdomain.mydomain.com``] Obtain: [``mysubdomain.mydomain.com``] creating new order: provisioning client: performing request: Get \"``https://acme-staging-v02.api.letsenctrypt.org/directory\``": dial tcp: lookup ``acme-staging-v02.api.letsencrypt.org`` on 127.0.0.53:53: read udp 127.0.0.1:55776 -> 127.0.0.53:53: read connection refused (ca=https://acme-staging-v02.api.letsencrypt.org/directory)"

3. Caddy version:

v2.11.9

4. How I installed and ran Caddy:

Through docker compose and it’s also installed in my system through sudo apt install caddy

a. System environment:

Ubuntu 26.04.1 LTS (Ubuntu Server)

b. Command:

docker compose up

c. Service/unit/compose file:

name: nextcloud-aio # Add the container to the same compose project to which all the sibling containers are added automatically
services:
  caddy:
    image: caddy:alpine
    restart: unless-stopped
    container_name: caddy
    cap_add:
      - NET_ADMIN
    ports:
      - "80:80"
      - "443:443"
      - "443:443/udp"
    volumes:
      - ./Caddyfile:/etc/caddy/Caddyfile
      - caddy_config:/config
      - caddy_data:/data
    networks:
      - proxy

volumes: # If you want to store the data on a different drive, see https://github.com/nextcloud/all-in-one#how-to-store-the-filesinstallation-on-a-separate-drive
  nextcloud_aio_mastercontainer:
    name: nextcloud_aio_mastercontainer # This line is not allowed to be changed as otherwise the built-in backup solution will not work
  caddy_config:
  caddy_data:

networks:
  proxy:
    external: true

In this same yaml there’s the stuff for NextCloud but that’s running well and is not relevant for this

d. My complete Caddy config:

{
        # Set this path to your site's directory
        root * /usr/share/caddy

        # Enable the static file server
        file_server
}


https://subdomain.domain.com:443 {
        header {
                Strict-Transport-Security "max-age=31536000; includeSubDomains; preload"
                X-Content-Type-Options "nosniff"
                Referrer-Policy "strict-origin-when-cross-origin"
                -Server
        }
        reverse_proxy localhost:11000
}

5. Links to relevant resources:

Type here