Virtual Server ("Port Forwarding") - Billion BiPAC 8500/8520 User Manual

Billion BiPAC 8500/8501/8520/8521 SHDSL (VPN) Firewall Bridge/ Router

Virtual Server ("Port Forwarding")

In TCP/IP and UDP network, a port is a 16-bit number used to identify which application
program (usually a server) incoming connections should be delivered to. Some ports have
numbers that are pre-assigned to them by the IANA (the Internet Assigned Numbers Authority),
and these are referred to as "well-known ports". Servers follow the well-known port assignments
so clients can locate them.
If you wish to run a server on your network that can be accessed from WAN (i.e. from other
machines on the Internet outside your local network), or any application that can accept
incoming connections (e.g. Peer-to-peer/P2P software such as instant messaging applications
and P2P file-sharing applications) and are using NAT (Network Address Translation), then you
will usually need to configure your router to forward these incoming connection attempts using
specific ports to the PC on your network running the application. You will also need to use port
forwarding if you want to host an online game server.
The reason for this is that when using NAT, your publicly accessible IP address will be used by
and point to your router, which will then deliver all traffic to the private IP addresses used by
your PCs. Please see the WAN configuration section of this manual for more information on
NAT.
The device can be configured as a virtual server so that remote users accessing services such
as Web or FTP services via the public (WAN) IP address can be automatically redirected to the
local servers in the LAN network. Depending on the requested service (TCP/UDP port number),
the device will redirects the external service request to the appropriate server within the LAN
network
Add Virtual Server
Because NAT can act as a "natural" Internet firewall, your router protects your network from
being accessed by outside users when using NAT, as all incoming connection attempts will point
to your router unless you specifically create new Virtual Server entries to forward those ports to
a PC on your network.
When your router needs to allow outside users to access internal servers, e.g. a web server,
FTP server, Email server or game server, the router can act as a "virtual server". You can set up
a local server with a specific port number for the service to use, e.g. web/HTTP (port 80), FTP
(port 21), Telnet (port 23), SMTP (port 25), or POP3 (port 110), When an incoming access
request to the router for a specified port is received, it will be forwarded to the corresponding
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Chapter 4: Configuration