Network security from malicious activity can be enhanced by enabling PPTP filtering on the PPTP server. When PPTP filtering is enabled, the PPTP server on the private network accepts and routes only PPTP packets from authenticated users. This prevents all other packets from entering the PPTP server and private network. In conjunction with PPP encryption, this ensures that only authorized encrypted data enters or leaves the private LAN.
PPTP filtering is enabled on the PPTP server using the Protocols tab in the Network option of Control Panel. For step-by-step instruction on enabling PPTP filtering, see the white paper titled “Installing, Configuring, and Using PPTP with Microsoft Clients and Servers.”