Digital Ocean Dynamic DNS Service

A simple nodejs based namecheap compatible dynamic DNS updated service for Digital Ocean. The service includes a single endpoint /update that expects a PUT request with domain, host, password and ip parameters. It then makes a call to the Digital Ocean Version 2 API to update an associated A record to point to the provided IP.

Why

The UniFi Security Gateway provides built-in support for a limited number of dynamic DNS services. They don't provide support for Digitial Ocean and namecheap was one of the few they supported that didn't leverage basic auth. With this service you can select namecheap from the Dynamic DNS service list and specify the server where this service is running in the server field to have the USG reach out to this service. The value for hostname will be sent as the host parameter, username will be sent as domain and password will be sent as password.

Security

The service should be run behind a proxy which has SSL enabled like nginx, apache, or something else. It can also be modified to start the service with SSL itself but that is beyond the scope of this README. There is very basic security built-in to the service in the form of the query parameter password which is then hashed using scrypt and compared to the HASHED_CREDENTIALS value from the configuration file. Before the hashes are checked the host and domain query parameters are used to find a corresponding DNS record ID in the DOMAINS configuration map. If no matching domain is found a 403 is returned before attempting to compare the password hash.

Service Configuration

The service relies on a config file config.json and example of the configuration file is provided.

• API_TOKEN is the token used to communicate with the digital ocean API. You can generate a token on the Apps & API page of your account. The token will need to have WRITE access.
• HASHED_CREDENTIALS should be the base64 encoded string for an scrypt generate "secret" hash. You can generate this value after you've done an npm install from this directory via the node command line:

localhost:do-dyndns root$ node
> const scrypt = require('scrypt');
undefined
> let password = 'SECRET';
undefined
> scrypt.hashSync(password, {'N': 2,'r': 1,'p': 1}, 64, password).toString('base64');
'SNRxlb5dmc5jvs5amUzKPIwq0glkBxvUapBtUkbjlWc3uOXakGgh0LO14ZksyMAjJA9xQvMrmlh9IqaXO020yQ=='

• SERVER_CONFIG is a (hapi server configuration object)[https://hapijs.com/api/16.6.2#serverconnectionoptions]

Using Docker

The service can be run as a docker container using the standard service port 8002 using the provided Dockerfile. A Makefile has also been included for convenience and supports the following commands:

• build - builds the do_dyndns docker image
• run - runs the service in docker using the do_dyndns image
• clean - stops and removes and containers using the do_dyndns image and removes the image

License

Copyright (c) 2018 Kyle Lilly (kylelilly@gmail.com)

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.