certbot-dns-asd

A Certbot DNS plugin using the All Secure Domains (ASD) dyanmic DNS API.

ASD offer a secure DNS update API (with fine-grained access control on a per-record basis). This plugin allows certbot to use the ASD DNS update API to carry out an RFC8555 section 8.4 "dns-01" challenge, without the security issues associated with many other providers' DNS APIs.

The API can be used to obtain an SSL certificate from the "Let's Encrypt" service.

License

This software is Copyright 2018 to 2023 by SEOSS Ltd, and offered under the GNU General Public License version 3, see the file LICENSE (which you should have recieved with this software) for more information.

Upgrading From v0.0.1

Namespace handling in Certbot has changed, and this plugin has been changed since v0.0.1 to use the new API, so the following modifications must be made to existing configurations files (e.g. /etc/letsencrypt/renewal/*.conf files).

Change the following lines:

[renewalparams]
authenticator = certbot-dns-asd:dns
certbot_asd:dns_credentials = ...

to:

[renewalparams]
authenticator = dns-asd
dns_asd_credentials = ...

Installation

• It is no longer recommended to install python packages into the "system" python.

1. Install Certbot using the pip install instructions at: https://certbot.eff.org/instructions?ws=other&os=pip

2. Run the following command as root: /opt/certbot/bin/pip install git+https://github.com/tim-seoss/certbot-dns-asd.git

Usage

The following example assumes you wish to obtain an SSL certificate for the host my-ssl-hostname.example.com, and that you are managing the DNS for the example.com domain using the ASD DNS service...

1. Using the ASD control panel, add one or more DNS dynamic update TXT records of the form _acme-challenge.my-ssl-hostname within the example.com DNS management settings. For each newly created _acme-challenge TXT record, tick the Enable dynamic (API) upates box. Copy the "UUID" which ASD provides you for the record(s) and use them in steps below.

2. To obtain wildcard certificates, e.g. for *.example.com, you will need to create a TXT record at _acme-challenge.example.com (note there is no * in the DNS record name, see also the note below if you need to obtain a certificate for both example.com and *.example.com).

3. Create a JSON file based on the following example:

   {
           "dns_api_keys": {
                   "_acme-challenge.my-ssl-hostname.example.com": {
                           "domain": "example.com",
                           "key": "aaee0065-9d22-4070-8546-14b5c0f17328"
                   },
                   "_acme-challenge.my-other-ssl-hostname.example.com": {
                           "domain": "example.com",
                           "key": "ebacdd45-d71d-46f0-b9f1-194fe9491855"
                   }
           }
   }

   e.g. in the location /etc/letsencrypt/asd-dns-api/example_com.json

   Be sure to restrict the permissions on the file and/or directory to prevent reading by unprivileged users.

4. Optionally obtain a test (Let's Encrypt staging server) certificate:

   me@server:~$ certbot --staging --authenticator dns-asd \
   --dns-asd-credentials /etc/letsencrypt/asd-dns-api/example_com.json \
   certonly -d my-ssl-hostname.example.com -d my-other-ssl-hostname.example.com
   

5. Optionally change the certonly command to automatically install the newly obtained certificate for application server using the --installer option. See https://certbot.eff.org/docs/using.html#combining-plugins and https://certbot.eff.org/docs/using.html#combining-plugins .

6. Once you have finished testing, obtain a production certificate by repeating your previous command, having first removed the --staging argument to certbot.

If your certificate request will need more than one challenge to be verified against a single TXT record (e.g. if you request a single certificate, which is valid for both example.com and the wildcard *.example.com, then you will need to create multiple records via the ASD control panel, and then list the corresponding multiple keys like this:

    {
            "dns_api_keys": {
                    "_acme-challenge.example.com": {
                            "domain": "example.com",
                            "key": ["e18a608f-e5c2-418f-bfd5-847df39280a8", "5f91a2f8-5797-4b4e-a723-3adfcb1c2c88"]
                    }
            }
    }

Bugs?

Please open an issue at https://github.com/tim-seoss/certbot-dns-asd/issues