MCSE Windows 2000 Network Infrastructure Exam Cram 2 (Exam Cram 70-216)

Configuring TCP/IP Packet Filters

For increased security, you can implement IP packet filters to control the type of inbound IP traffic allowed to enter your computer and/or network. Inbound traffic can be filtered by destination TCP port, destination UDP port, and by IP protocol type.

Implementing IP Packet Filters

Use the following process to implement IP packet filters:

1. Within the Network and Dial-up Connections applet, right-click the Local Area Connection and select Properties.

2. Select the Internet Protocol (TCP/IP) and click the Properties button.

3. From the Internet Protocol (TCP/IP) Properties window, click the Advanced button and select the Options tab (see Figure 5.7).

   Figure 5.7. Configuring TCP/IP options.

4. From the Optional Settings list, select TCP/IP Filtering and click Properties.

5. The TCP/IP Filtering window appears. To enable filtering, select the check box beside the Enable TCP/IP filtering option (see Figure 5.8).

   Figure 5.8. Enabling TCP/IP filtering.

By default, traffic on all TCP and UDP ports are allowed. To specify the type of traffic allowed to reach your computer, select one of the Permit Only options (depending on whether you want to configure TCP, UDP, or protocols) and click Add. If you are configuring TCP and UDP traffic, you will specify the port number (Tables 5.3 and 5.4 summarize some of the common ports used by TCP and UDP). To configure protocols, specify the type of IP protocol to which you want to allow access.

Table 5.3. TCP Ports

Table 5.4. UDP Ports