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Chapter 3: Advanced Confi guration
34 Chapter 3
Network Web Page Group
WAN Web Page (Fig. 22)
This page gives you the ability to enter some data your cable company may require, as explained
before in Mandatory User Confi guration. In addition, it enables you to view your WAN side IP
address and lease information.
Your gateway can provide NAT/PAT (Network and Port Address Translation) as an element of
security to prevent others from reaching your PCs when not authorized. To accomplish this, the
gateway watches packets you send from your PC to Internet sites. Each time you send to a site
(destination IP address) and application at that site (port), it translates your PC’s original IP and
source port to new ones, and adds a row to its Connection Table maintained internally. (Note the
different meaning of ‘connection’ here to describe an IP connection versus a physical cabling
connection). If and when that site/application replies, it looks up the connection and reverses the
IP/port process to direct the response to your PC.
The Connection Table manages itself, but you can also force this table to be cleared manually. To
do this, click the Renew NAT Lease button.
You can enter a spoofed MAC address that causes your gateway networking stack to use that
MAC address when communicating instead of the usual WAN MAC address (CM label + 2, as
explained in Chapter 2). Enter the desired MAC address and click Apply.
Caution: If you enter a MAC address in use by another party, it can cause an address confl ict on
the network that could affect both you and that party.
Fig. 22
DCW725 book file.indb 34 DCW725 book file.indb 34 10/6/04 11:17:27 AM10/6/04 11:17:27 AM