No – SSL certificates can no longer be used to secure your company’s internal websites, intranets or IP address.
This is because internal servers are vulnerable to ‘man-in-the-middle’ attacks, in which attackers will use a copy of the real certificate to intercept and eavesdrop on any form of online communication.
For alternative ways on how to set up an SSL certificate, please read the following article: How can I add an SSL certificate to my domain/website?