Diagram

Draytek Vigor 2925 Dial-out configuration

To successfully connect the Draytek & Billion, select IPsec Security Method with High ESP and select DES without Authentication

Dial-out

Billion Router configure as Dial-in

On the Billion select DES as the Encryption Algorithm

Billion router

Note :

1. For some Billion Router models, IPsec is set to Dial-out only. In that case, set the Draytek router to Dial-in mode.

2. The IPsec Security Method may be different on different Billion models and may need adjustment if the VPN cannot connect.