Private IP addresses at Allowed Callback Urls

Hello,
We want to use Auth0 in an Angular application to authenticate users. The problem is that all our users connect to the Web Application through the Private IP address in which the server is located in their private network. How would it be possible to allow any Redirect Callback URL that follows the format of an IP address or anything similar? As the client may change the IP address of the web server, there are millions of possible addresses and adding all possibilities to the Allowed Callback URLs list is just impossible.
Thank you very much.