[Koha] Koha Networking issues

Hello, I'm a librarian in a public library and we recently installed koha in the library server via a virtual machine using Oracle Virtual-Box and assigned it a pubic IP, to enable worldwide access of the opac. However, there has been a lot of Internet fluctuations in the library which has been inconveniencing the circulation of books making the library staffs to make use of offline circulation in the busy library. I was asking whether there is a way to enable private IP inside the organization local network to be used as a fallback network when the Internet is lost. Kindly assist