Installation

Since this package acts as a plugin for certbot, the installation method can vary depending on how certbot is installed.

pip install certbot-dns-netcup

uv tool install certbot --with certbot_dns_netcup

uvx --from certbot --with git+https://github.com/coldfix/certbot-dns-netcup \
    [...options...]

sudo snap install certbot-dns-netcup

sudo snap set certbot trust-plugin-with-root=ok
sudo snap connect certbot:plugin certbot-dns-netcup

docker pull docker.io/coldfix/certbot-dns-netcup

docker pull ghcr.io/coldfix/certbot-dns-netcup

Usage

To acquire a single certificate for both example.com and *.example.com, waiting 1200 seconds (20min) for DNS propagation:

certbot certonly \
  --authenticator dns-netcup \
  --dns-netcup-credentials ~/.secrets/certbot/netcup.ini \
  --dns-netcup-propagation-seconds 1200 \
  --keep-until-expiring --non-interactive --expand \
  --server https://acme-v02.api.letsencrypt.org/directory \
  -d 'example.com' \
  -d '*.example.com'

The parameters and the format of the credentials file are described below.

Named Arguments

To start using DNS authentication for netcup, pass the following arguments on certbot’s command line:

NOTE: You may need to set an unexpectedly high propagation time (≥ 900 seconds) to give the netcup DNS time to propagate the entries! This may be annoying when calling certbot manually but should not be a problem in automated setups. In exceptional cases, 20 minutes may be required. See #28.

Credentials

Use of this plugin requires a configuration file containing netcup API credentials, obtained from your netcup account page. You need a different API key depending on whether your domains are managed by CloudDNS.

• If they are managed by CloudDNS (you will see a CloudDNS tab in the CCP when you click on the domain), you have to use an API key for the new API (section >_ API-Keys in your account page). See also: netcup API.

• If they are not yet on CloudDNS, you have to use an API key for the legacy API (Legacy API-Keys section). See also: CCP API.

For the new netcup API (CloudDNS), the credentials.ini file looks like this:

dns_netcup_api_v1_key   = 0123456789abcdef0123456789abcdef01234567

For the legacy API (no CloudDNS), the credentials.ini has to contain these entries:

dns_netcup_customer_id  = 123456
dns_netcup_api_key      = 0123456789abcdef0123456789abcdef01234567
dns_netcup_api_password = abcdef0123456789abcdef01234567abcdef0123

Both sets of values can be present in the credentials.ini file. In this case, the old API is used as fallback if your domains are not yet managed by CloudDNS.

The path to this file can be provided interactively or using the --dns-netcup-credentials command-line argument. Certbot records the path to this file for use during renewal, but does not store the file’s contents.

CAUTION: You should protect these API credentials as you would the password to your netcup account. Users who can read this file can use these credentials to issue arbitrary API calls on your behalf. Users who can cause Certbot to run using these credentials can complete a dns-01 challenge to acquire new certificates or revoke existing certificates for associated domains, even if those domains aren’t being managed by this server.

Certbot will emit a warning if it detects that the credentials file can be accessed by other users on your system. The warning reads “Unsafe permissions on credentials configuration file”, followed by the path to the credentials file. This warning will be emitted each time Certbot uses the credentials file, including for renewal, and cannot be silenced except by addressing the issue (e.g., by using a command like chmod 600 to restrict access to the file).

Docker

You can pull the latest version of the docker image directly from Docker Hub as follows:

docker pull coldfix/certbot-dns-netcup

Alternatively, the docker image can be built from a local checkout and the included Dockerfile as follows:

docker build -t coldfix/certbot-dns-netcup .

Once that’s finished, the application can be run as follows:

docker run --rm \
  -v /var/lib/letsencrypt:/var/lib/letsencrypt \
  -v /etc/letsencrypt:/etc/letsencrypt \
  --cap-drop=all \
  coldfix/certbot-dns-netcup certbot certonly \
    --authenticator dns-netcup \
    --dns-netcup-propagation-seconds 900 \
    --dns-netcup-credentials /var/lib/letsencrypt/netcup_credentials.ini \
    --keep-until-expiring --non-interactive --expand \
    --server https://acme-v02.api.letsencrypt.org/directory \
    --agree-tos --email "webmaster@example.com" \
    -d example.com -d '*.example.com'

You may want to change the volumes /var/lib/letsencrypt and /etc/letsencrypt to local directories where the certificates and configuration should be stored.