Google Analyics behind a Firewall or Non-public Website
According to the Google documentation, In order for Google Analytics to generate reports for your corporate intranet usage, your corporate network must be able to reach the ga.js JavaScript file at http://www.google-analytics.com/ga.js or https://www.google-analytics.com/ga.js.
If you can reach the above URL using your company Internet connection, you have satisfied the first requirement. Additionally, your intranet must be accessible through a fully qualified domain name such as http://intranet.example.com. The ga.js JavaScript will not work if your intranet can only be accessed using a domain name that is not fully qualified, such as http://intranet.example.com.