How to prevent WebRTC Leak?

I am currently using AR750S-Ext Slate with OpenVPN (KeepSolid VPN Unlimited VPN Service) as a client and tested for WebRTC leaks and my current IP address is leaked.

I cannot install anything in the laptop (including extensions on the browser) nor change the browser configuration. But, how to prevent WebRTC leaks?

Will adopting Home VPN Server ( GL-MT300N-V2(Mango)) and portable VPN Client (AR750S-Ext Slate) approach address this issue?