Yes. Configuring the Rublon Authentication Proxy on the same IP server as your identity provider (FreeRADIUS, Active Directory, OpenLDAP, etc.) is possible.
If you want to have the Rublon Authentication Proxy and an Identity Provider (IdP) on the same server, you must ensure they listen on different port numbers.
You can change the port the Rublon Authentication Proxy is listening on by opening your Rublon Auth Proxy\config\config.json configuration file and changing the value of PORT in the SERVERS section.