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52
C
HAPTER
4: C
OMMAND
R
EFERENCE
For the other settings, specify the
DNS Serve
rs. Up to three
DNS servers can be specified, although not all have to be
used. The Internet Firewall uses these servers to look up the
addresses of machines used to download the Web Site
Filter and for the built-in
DNS Lookup
tool.
Type the required values and click
Update
to send the
configuration data to the Internet Firewall. It is necessary to
restart the Internet Firewall for these changes to take
effect.
NAT Enabled
Network Address Translation
(NAT) provides anonymity to
machines on the LAN by connecting the entire network to
the Internet using a single IP address. This is useful for two
purposes:
■
Additional security is provided because all the addresses
on the LAN are invisible to the outside world.
■
In cases where a network uses invalid IP addresses or if
addresses are in short supply, NAT can be used to
connect the LAN to the Internet without changing the
IP addresses of computers and other devices on the
LAN.
Remote authenticated access is not possible with NAT
enabled.
When using IP addresses on a LAN which have not been
assigned by an Internet Service Provider, it is a good idea to
use addresses from a special address range allocated for
this purpose. The following IP address ranges can be used
for private IP networks and do not get routed on the
Internet:
10.0.0.0 - 10.255.255.255
172.16.0.0 - 172.31.255.255
192.168.0.0 - 192.168.255.255
Select
NAT Enabled
from the
Network Addressing Mode
drop-down list if the network uses private IP addresses or if
addresses are in short supply. A window similar to that in
Figure 17
is displayed.
Summary of Contents for 3C16772 - OfficeConnect Web Site Filter
Page 8: ......
Page 16: ...16 ABOUT THIS GUIDE ...
Page 34: ...34 CHAPTER 2 INSTALLING THE HARDWARE ...
Page 126: ...126 CHAPTER 5 THE OFFICECONNECT WEB SITE FILTER ACTIVATION ...
Page 132: ...132 APPENDIX A CABLE SPECIFICATIONS AND PINOUT DIAGRAM Figure 52 Twisted Pair Pinouts ...
Page 158: ...158 APPENDIX E EXAMPLE CONFIGURATIONS ...
Page 172: ......
Page 178: ...178 INDEX ...