19216811.liveChapter 15 Network Address Translation (NAT)
NBG-419N User’s Guide
131
In addition to the servers for specified services, NAT supports a default server. A service request
that does not have a server explicitly designated for it is forwarded to the default server. If the
default is not defined, the service request is simply discarded.
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.
Port forwarding allows you to define the local servers to which the incoming services will be
forwarded. To change your NBG-419N’s port forwarding settings, click
Network > NAT
>
Application
. The screen appears as shown.
Note: If you do not assign a
Default Server
IP address
in the
NAT >
General
screen,
the NBG-419N discards all packets received for ports that are not specified in this
screen or remote management.
Refer to
Appendix E on page 259
for port numbers commonly used for particular services.
Figure 94
Network > NAT > Application
The following table describes the labels in this screen.
Table 58
Network > NAT > Application
LABEL
DESCRIPTION
Add Application Rule
Active
Select the check box to enable this rule and the requested service can be
forwarded to the host with a specified internal IP address.
Clear the checkbox to disallow forwarding of these ports to an inside server
without having to delete the entry.
Service Name
Type a name (of up to 31 printable characters) to identify this rule in the first
field next to
Service Name
. Otherwise, select a predefined service in the second
field next to
Service Name
. The predefined service name and port number(s)
will display in the
Service Name
and
Port
fields.