Unfortunately, if the Internet-ID connection is used, the LAN IP address won't be shown, but we plan to implement such feature in the future. Also, if there is a VPN connection between Viewer and Host you can connect directly using the VPN IP address of the remote Host.
Please try switching to the Details view style on the View tab in the main Viewer window. There's an IP address field displayed where you can see the Host's IP address if the direct connection was established: If you connected to the Host using an Internet-ID connection, the Internet-ID Server address will be shown, whether public server or self-hosted server is used.
We plan to implement a feature which shows an IP address of the Host even if the Internet-ID connection is used in the future.