You would have to ask the service if they use port forwarding or not. As to WebRTC, you change that in your browser.
https://browserleaks.com/webrtc#webrtc-disable
I don't see the option in IE. You might want to use Firefox, Cyberfox or PaleMoon. Use the addons NoScript, uBlock, HTML5 Local Storage Explorer and Betterprivacy. You will have better security. NoScript can be very cumbersome though. To combat this you can do one of two things. Either go into Addons and disable NoScript and it will ask you if you just want basic protection, or what ever it's called. Say yes. Or go into NoScript's options and allow base 2nd level domains by default. That will help. But some sites have so many bloody third party scripts to add website content that you may end up just allowing the whole site temporally. The addon HTML5 Local Storage Explorer will appear in the Tools option above in the browser. This is important as websites are now using HTML5 to store a cookie in your local storage. With this addon you can delete them. It would be best to set the browser options to clear cache and cookies on browser exit. There's more, but I want drag this out.
Anyway... VPN.AC is 4.90/month and they don't use port forwarding as they know that will expose your real IP address. Plus the XOR or ECC encryption option using port 443 is great so that your ISP thinks the encrypted data is just website encrypted traffic. This is especially useful to China users to get past the "Great Firewall."
https://vpn.ac/
