How to Enable PPTP Packet Filtering, RAS, and Proxy Server 2.0

By default, packet filtering is enabled (using the Enable packet filtering on external interface check box on the Packet Filters tab). This blocks all packets on the external interface until an access request is made. To enable dynamic packet filtering, click to select the Enable dynamic packet filtering of Microsoft Proxy Server packets check box. This enables the filters in the Exceptions list. When an access request is made, service is enabled only for the type of packets allowed by the Exceptions list.

Using Packet Filtering

Proxy Server contains the "PPTP call" and "PPTP receive" predefined packet filters. You should add these filters to your configuration so you have the ability to make outbound and inbound Point-to-Point Tunneling Protocol (PPTP) connections to the Proxy Server host.

You can use Proxy Server's packet filtering on traffic passing through PPTP virtual interfaces. As usual, packets with addresses that are not included in the Local Address Table (LAT) are treated as external traffic.

How to Enable Packet Filtering for a PPTP Connection

1. In the Microsoft Internet Information Server (IIS) console, right-click Web Proxy, and then click Properties.
2. Click Security.
3. Click to select the Enable dynamic packet filtering on external interface check box, and then click Add.
4. Click Predefined Filter.
5. Add PPTP Call.
6. Add PPTP Receive.
7. Stop and start the Web Proxy service.

For additional information, click the article numbers below to view the articles in the Microsoft Knowledge Base: