Specify Network Settings
55
VDSL Voice Gateway
•
Default DMZ Server
. This feature is sometimes helpful when you are playing online
games or videoconferencing but it makes the firewall security less effective. See
•
Respond to Ping on Internet Port
. This feature allows your gateway to be
discovered. Use this feature only as a diagnostic tool or if you have a specific reason.
•
Disable IGMP Proxying
. IGMP proxying allows a computer on the local area network
(LAN) to receive multicast traffic from the Internet. If you do not need this feature, you
can select this check box to disable it.
•
MTU Size (in bytes)
. The normal MTU (maximum transmit unit) value for most
Ethernet networks is 1500 bytes, or 1492 bytes for PPPoE connections. Change the
MTU only if you are sure that it is necessary for your Internet connection. See
55.
•
Disable SIP ALG
. Some VoIP applications do not work well with the SIP ALG.
Selecting this check box to turn off the SIP ALG might help your VoIP devices to
create or accept a call through the gateway.
•
NAT Filtering
. Network Address Translation (NAT) determines how the gateway
processes inbound traffic. Secured NAT protects computers on the LAN from attacks
from the Internet but might prevent some Internet games, point-to-point applications,
or multimedia applications from working. Open NAT provides a much less secured
firewall but allows almost all Internet applications to work.
6.
Click the
Apply
button.
Your changes are saved.
Default DMZ Server
The default DMZ server feature is helpful when you are using some online games and
videoconferencing applications that are incompatible with Network Address Translation
(NAT). The gateway is programmed to recognize some of these applications and to work
correctly with them, but other applications might not function well. In some cases, one local
computer can run the application correctly if the IP address for that computer is entered as
the default DMZ server.
WARNING:
DMZ servers pose a security risk. A computer designated as the
default DMZ server loses much of the protection of the firewall and
is exposed to exploits from the Internet. If compromised, the DMZ
server computer can be used to attack other computers on your
network.
The gateway usually detects and discards incoming traffic from the Internet that is not a
response to one of your local computers or a service that you have configured in the Port
Forwarding/Port Triggering screen. Instead of discarding this traffic, you can have the
