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

Once there, Click on the Security Tab

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.