Right after you create your opensolr Index, simply click on it's name, in the Opensolr Control Panel.

In there, you have the two options.
- Add new Access IP Address (you can see the default is that all is reaching /, which means that all IPs are able to see ALL of your Solr Request Handlers).
- Manage HTTP Auth Credentials for your solr index.

Please Contact Us if you need more help on how to protect your index.