Innoband 8860-C1, User Manual

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Chapter 4: Configuration 103
Virtual Server (Port Forwarding)
In TCP/IP and UDP networks a port is a 16-bit number used to identify which application program (usually a
server) incoming traffic 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 the WAN side (i.e. from other
machines on the Internet that are 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 need to configure your
gateway to forward these incoming connection attempts using specific ports to the PC on your network
running the application.
The reason for this is that when using NAT, your publicly accessible IP address will be used by and point to
your gateway, which then needs to 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 local servers in the LAN
network. Depending on the requested service (TCP/UDP port number), the device 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 gateway protects your network from being
accessed by outside users when using NAT since all incoming connection attempts will point to your
gateway unless you specifically create Virtual Server entries to forward those ports to a PC on your
network.
When your gateway needs to allow outside users to access internal servers (web server, FTP server, Email
server or game server), the gateway 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 gateway for a specified port is
received, it will be forwarded to the corresponding internal server.