1. Overview In that documentation, we will explain how to configure OpenOTP multi-factor authentication on your Microsoft Network Policy Server. As a practical example, we will configure NPS with Microsoft Remote Access Server for VPN use. For this recipe, you will need to have a WebADM, OpenOTP and Radius Bridge installed and configured. Please refer to WebADM Installation Guide, WebADM Manual and Radius Bridge Manual for instructions on these. Your Microsoft Network Policy Server and Remote Access Server should be installed and configured for VPN (PPTP, SSTP) use.