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DG-BG4300N User Manual
Fields in this page:
Field
Description
Service Type
Select a service from pull-down menu or User-defined Service Name.
Protocol
There are 2 options available: TCP, UDP.
WAN Setting
There are 2 options available: create rules by interface or by IP address
WAN Interface
Select the WAN interface on which the Virtual Server rule is to be
applied.
WAN Port
The destination port number that is made open for this application on
the WAN-side
Local IP Address
IP address of your local server that will be accessed by Internet.
LAN Open Port
The destination port number that is made open for this application on
the LAN-side.
Function buttons for the setting block:
Apply Changes
Click to save the rule entry to the configuration.
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Function buttons for the Current Table:
Delete Selected
Delete the selected rules from the table. You can click Delete button from the Current virtual serve
forwarding table.
Disable
Without deleting the rule you can make specific virtual server entry in the table as inactive. You can click
Disable to de-activate the entry.
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6.2.3 NAT Forwarding Setup
Entries in this table allow you to automatically redirect common network services to a specific machine
behind the NAT firewall. These settings are only necessary if you wish to host some sort of server like a
web server or mail server on the private local network behind your Gateway's NAT firewall.
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6.2.4 NAT ALG and Pass-Through
An application-level gateway (also known as
ALG
or application layer gateway) consists of a security
component that augments a firewall or NAT employed in a computer network. It allows customized NAT
traversal filters to be plugged into the gateway to support address and port translation for certain
application layer "control/data" protocols such as IPSec, L2TP, PPTP, FTP, SIP, RTSP etc. In order for
these protocols to work through NAT or a firewall, either the application has to know about an
address/port number combination that allows incoming packets, or the NAT has to monitor the control
traffic and open up port mappings (firewall pinhole) dynamically as required. Legitimate application data
can thus be
passed through
the security checks of the firewall or NAT that would have otherwise
restricted the traffic for not meeting its limited filter criteria.
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6.2.5 NAT EXCLUDE IP Setup
The purpose is to exclude certain flows of traffic from translation. Any packets (going from
inside or outside) matching the NAT EXCLUDE IP do not require NAT translation entries to be
permitted by the router.
6.2.6 NAT Port Trigger
Port triggering is a way to automate port forwarding in which outbound traffic on predetermined
ports ('triggering ports') causes inbound traffic to specific incoming ports to be dynamically
forwarded to the initiating host, while the outbound ports are in use. This allows computers
behind a NAT-enabled router on a local network to provide services that would normally
require the computer to have a fixed address on the local network. Port triggering triggers can
open an incoming port when a client on the local network makes an outgoing connection on a
predetermined port or range of ports.
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