RangeMax Wireless-N DSL Gigabit Modem Router DGN3500 User Manual
Advanced Configuration 5-3
v1.0, November 2009
Setting Up a Default DMZ Server
The default demilitarized zone (DMZ) server feature is helpful when you use some online games
and videoconferencing applications that are incompatible with NAT. The modem router is
programmed to recognize some of these applications and to work correctly with them, but there
are other applications that might not function well. In some cases, one local computer can run the
application correctly if that computer’s IP address is entered as the default DMZ server.
Incoming traffic from the Internet is usually discarded by the modem router unless the traffic is a
response to one of your local computers or a service that you have configured in the Ports screen.
Instead of discarding this traffic, you can have it forwarded to one computer on your network. This
computer is called the default DMZ server.
To assign a computer or server to be a default DMZ server:
1. Log in to the modem router at its default LAN address of http://192.168.0.1 with its default
user name of admin and default password of password, or using whatever user name,
password, and LAN address you have chosen for the modem router.
2. In the main menu, under Advanced, click WAN Setup to display the following screen.
3. On the WAN Setup screen, select the Default DMZ Server check box.
4. Type the IP address for that server.
5. Click Apply to save your changes.
MTU Size (in bytes) The normal MTU (Maximum Transmit Unit) value for most Ethernet networks
is 1500 bytes, or 1492 Bytes for PPPoE connections. For some ISPs you
might need to reduce the MTU. This is rarely required, and should not be done
unless you are sure it is necessary for your ISP connection. See “Changing
the MTU Size” on page 7-6.
Disable SIP ALG The Session Initiation Protocol (SIP) Application Level Gateway (ALG) is
enabled by default to optimize VoIP phone calls that use the SIP. The Disable
SIP ALG check box allows you to disable the SIP ALG. Disabling the SIP ALG
might be useful when running certain applications.
Note: For security reasons, you should avoid using the default DMZ server feature. When
a computer is designated as the default DMZ server, it loses much of the protection
of the firewall, and is exposed to many exploits from the Internet. If compromised,
the computer can be used to attack your network.
Table 5-1. WAN Setup Settings
Setting Description