Table of Contents
Advertisement
3.3.4.3 NAT -- Virtual Servers Setup
In its default state, DSL router blocks all external users from connecting to or communicating
with your net-work. Therefore the system is safe from hackers who may try to intrude on the
network and damage it. However, you may want to expose your network to the Internet in
certain limited and controlled ways in order to enable some applications to work from the
LAN (game, voice and chat applications, for example) and to enable Internet-access to
servers in the home network. The Port Forwarding feature supports both of these
functionalities. If you are familiar with networking terminology and concepts, you may have
encountered this topic referred to as "Local Servers" The Port Forwarding screen lets you
define the applications that require special handling by DSL router .All you have to do is
select the application protocol and the local IP address of the computer that will be using or
providing the service. If required, you may add new protocols in addition to the most
common ones provided by DSL router. For example, if you wanted to use a File Transfer
Protocol (FTP) application on one of your PCs, you would simply select FTP from the list and
enter the local IP address or host name of the designated computer. All FTP-related data
arriving at DSL router from the Internet will henceforth be forwarded to the specific computer.
Similarly, you can grant Internet users access to servers inside your home network, by
identifying each service and the PC that will provide it. This is useful, for example, if you
want to host a Web server inside your home network. When an Internet user points his/her
browser to DSL router external IP address, the gateway will forward the incoming HTTP
request to your Web server. With one external IP address (DSL router main IP address),
different applications can be assigned to your LAN computers, however each type of
application is limited to use one computer. For example, you can de net hat FTP will use
address X to reach computer A and Telnet will also use address X to reach computer A, but
attempting to define FTP to use address X to reach both computer A and B will fail. DSL
router therefore provides the ability to add additional public IP addresses to port forwarding
rules, which you must obtain from your ISP, and enter into the NT IP Addresses Pool (see
section 7.3.7). You will then be able to define FTP to use address X to reach computer A and
address Y to reach computer B. Additionally, port forwarding enables you to redirect traffic to
a different port instead of the one to which it was designated. Lets say, that you have a Web
server running on your PC on port 8080 and you want to grant access to this server to any
one who accesses DSL router via HTTP To accomplish this, do the following:
Define a port forwarding rule for the HTTP service, with the PC IP or host name.
Specify 8080 in the Forward to Port' field.
All incoming HTTP traffic will now be forwarded to the PC running the Web server on port
8080 when setting a port forwarding service; you must ensure that the port is not already in
use by another application, which may stop functioning. A common example is when using
SIP signaling in Voice over IP the port used by the gateway VoIP application (5060) is the
same port on which port forwarding is set for LAN SIP agents.
62
Advertisement
Table of Contents
