Nodejs with socket.io from site to Drupal

I have a custom admin pannel/site from where I will send messages to a Drupal site. I can send messages with socket.io and I can receive them to a client page on the same admin site. But how do I send these messages to a Drupal site?

Is there a way to do this? Where do I have to running the server.js from nodejs? On the admin pannel or the Drupal site? How do they talk to each other?

The admin site and the Drupal site are running on the same server.

Thanks