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room but allows water and electricity to travel through well-
insulated pipes in the wall to reach all parts of a building. Similarly,
a computer firewall prevents unauthorized communication from
gaining entry to your computer. You can open certain safe
communication ports—to allow email communication, for
example—but keep other ports sealed off from the outside world.
The WAN IP (Internet) Filter page lets you configure up to eight
filters, each with up to 10 rules, for allowing access to the LAN
from the Internet or vice versa. Unless you set up such rules, the
NAT firewall software in the ADSL Ethernet will reject all
unsolicited packets coming from the WAN.
For example, in order to receive files via FTP , you must select the
Enable check box, type your address in the LAN IP Address
field, and select ftp from the Protocol list, as shown above. You
can type the sender’s address in the WAN IP Address field if you
want to allow files to come in only from a certain person or
persons (optional).
The WAN IP Filter page provides the way to set up one of the
computers on your LAN for online gaming. Let’s say your standard
filter is Index #0. You can create Filter Index #2 that allows all
Internet traffic through to your computer. When you want to play
games online, you enable Filter #2, disable Filter #0, and on the
WAN Settings page set your WAN IP Filter selection to 2.