P.RG F4202N
© (2010) Pirelli Broadband Solutions S.p.A. All Rights Reserved. Proprietary Use Pursuant to Cover Page Instructions.
Security Section
HBK 939800036-A1
49
to the Router's external IP address, the gateway will forward the incoming HTTP
request to your Web server.
With one external IP address (Router's 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 define that FTP will use ad-
dress X to reach computer A and Telnet will also use address X to reach com-
puter A, but attempting to define FTP to use address X to reach both computer
A and B will fail. The Router therefore provides the ability to add additional pub-
lic IP addresses to port forwarding rules, which you must first obtain from your
ISP, and enter into the 'NAT IP Addresses Pool'. 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 in-
stead 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 anyone who accesses the Router via
HTTP. To accomplish this, do the following:
Define a port forwarding rule for the HTTP service, with the PC's 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 al-
ready in use by another application, which may stop functioning. A common ex-
ample is when using SIP signaling in Voice over IP - the port used by the gate-
way's VoIP application (5060) is the same port on which port forwarding is set
for LAN SIP agents.