ATL Telecom AM2 - Manual (Page 42)

ATL User Guide
AM2 G.SHDSL Modem 42
The screen will prompt the modified parameter. Check the parameters and press Restart to restart the modem
or press Continue to setup another parameter.
6.5.6 NAT/DMZ
NAT (Network Address Translation) is the translation of an Internet Protocol address (IP address) used within
one network to a different IP address known within another network. One network is designated the inside
network and the other is the outside. Typically, a company maps its local inside network addresses to one or
more global outside IP addresses and reverses the global IP addresses of incoming packets back into local IP
addresses. This ensures security since each outgoing or incoming request must go through a translation
process, that also offers the opportunity to qualify or authenticate the request or match it to a previous
request. NAT also conserves the number of global IP addresses that a company needs and lets the company
use a single IP address for communication in the Internet world.
DMZ (demilitarized zone) is a computer host or small network inserted as a "neutral zone" between a
company private network and the outside public network. It prevents outside users from getting direct access
to a server that has company private data.
In a typical DMZ configuration for an enterprise, a separate computer or host receives requests from users
within the private network to access via Web sites or other companies accessible on the public network. The
DMZ host then initiates sessions for these requests to the public network. However, the DMZ host is not able
to initiate a session back into the private network. It can only forward packets that have already been
requested.