Observa Telecom TD851W User Manual page 51

Enable DMZ: Check the box to enable DMZ function.
DMZ Host IP Address: Enter the specified IP Address for DMZ host on the LAN side.
Click Apply Changes to save your configuration.
Note:
After configuration, you need to click the Save button appeared on the left panel so that your
configuration can still take effect after the Router reboots.
4.3.2.2 Virtual Server
Choose "Advanced→NAT→Virtual Server", and then you can configure the Virtual Server in the
screen as shown in Figure 4-27.
The Virtual Server is the server or server(s) behind NAT (on the LAN). It allows a single host on
your LAN to provide the specified service to the Internet, for example Web server or FTP server,
which you can make visible to the outside world even though NAT makes your whole inside
network appear as a single machine to the outside world.
TD851W 150Mbps Wireless N ADSL2+ Modem Router User Guide
Figure 4-26
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