ZyXEL Communications P870HNU-51B User Manual page 152

Chapter 8 Network Address Translation (NAT)
You may enter a single port number or a range of port numbers to be forwarded, and the local IP
address of the desired server. The port number identifies a service; for example, web service is on
port 80 and FTP on port 21. In some cases, such as for unknown services or where one server can
support more than one service (for example both FTP and web service), it might be better to
specify a range of port numbers. You can allocate a server IP address that corresponds to a port or
a range of ports.
Note: Many residential broadband ISP accounts do not allow you to run any server
processes (such as a Web or FTP server) from your location. Your ISP may
periodically check for servers and may suspend your account if it discovers any
active services at your location. If you are unsure, refer to your ISP.
To access this screen, click Network > NAT. The following screen appears.
Figure 56 NAT Port Forwarding
The following table describes the labels in this screen.
Table 44 NAT Port Forwarding
LABEL
Service Name
WAN Interface
Server IP
Address
External Port
Start
External Port
End
152
DESCRIPTION
Select a pre-defined service from the drop-down list box. The pre-defined service
port number(s) and protocol will display in the External port, Internal port and
Protocol fields.
Otherwise, select User Define to open the Rule Setup screen where you can
manually enter the port number(s) and select the IP protocol.
Select the WAN interface through which the service is forwarded.
You must have already configured a WAN connection with NAT enabled.
Enter the IP address of the server for the specified service.
Enter the original destination port for the packets.
To forward only one port, enter the port number again in the External Port End
field.
To forward a series of ports, enter the start port number here and the end port
number in the External Port End field.
Enter the last port of the original destination port range.
To forward only one port, enter the port number in the External Port Start field
above and then enter it again in this field.
To forward a series of ports, enter the last port number in a series that begins
with the port number in the External Port Start field above.
P-870HNU-51b User's Guide