implemented based on Hurricane Electric DNS's Dynamic DNS (https://dns.he.net/docs) support.

## installation

you can install the plugin with:

• snap set certbot trust-plugin-with-root=ok
• snap install certbot-dns-he
• snap connect certbot:plugin certbot-dns-he

you should see dns-he in the output if the plugin has been installed successfully:

• certbot plugins | grep dns-he

## usage

### quick start

1. navigate to your zone on Hurricane Electric DNS (https://dns.he.net).
2. create a new TXT record:
   • set "Name" to _acme-challenge.<your-domain>, where <your-domain> is the domain name for which you're trying to get a certificate. e.g., create _acme-challenge.example.com if you are trying to get a certificate for example.com or *.example.com.
   • check "Enable entry for dynamic dns".
   • leave other fields as-is and click "Submit".
3. click on the "Generate a DDNS key" icon for the TXT record under the "DDNS" column.
4. set a key for this dynamic DNS entry. store this key somewhere safe.
5. create a file he-credentials.ini on your web server with the following content:
   • dns_he_keys={"_acme-challenge.<your-domain>": "<ddns-key>"}
   where <ddns-key> is the dynamic DNS key you created for this name earlier.
6. execute the certbot command with necessary arguments, e.g., certbot certonly --authenticator dns-he --dns-he-credentials he-credentials.ini -d example.com

IMPORTANT: Hurricane Electric only allows one dynamic DNS entry per name. as a result, you are unable to generate a single certificate for both a root domain and a wildcard domain (e.g. for both example.com and *.example.com), since that requires setting two different TXT records with the same name (e.g. _acme-challenge.example.com) at the same time.

### CLI options

the following options are added to certbot's command line interface:

• --authenticator dns-he: (required) use Hurricane Electric DNS authenticator.
• --dns-he-credentials <file>: (required) specify path to a credential file
• --dns-he-propagation-seconds <seconds>: (optional) specify how long to wait before the TXT record is verified. defaults to 10.

### credential file

the credential file expects the following key-value pair:

• dns_he_keys: a JSON object with fully quantified domain names as keys and the corresponding dynamic DNS keys as values