User`s guide

Configuration through the web interface
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– Forward TCP/UDP/FTP connections from external networks to the following
internal devices: Specifies a list of connections based on a specific IP port and where
those connections should be forwarded to. Typically the connecting devices come from
the public side of the network and are redirected to a device on the private side of the
network.
It is possible to forward a single port or a range of ports. To forward a range of
ports, specify the number of ports in the range, in the Range Port Count field for
the port forwarding entry. When a range is configured, the first port in the range is
specified, and the full range is indicated in the displayed entry information.
Note that FTP connections require special handling by NAT. This is because the
FTP commands and replies are character-based, and some of them contain port
numbers in this message text. Those embedded port numbers potentially need to be
translated by NAT as messages pass between the private and public sides of the
network. In consideration of these needs, one should select FTP as the protocol type
when configuring a rule for FTP connection forwarding to an FTP server on the
private network side. If TCP is used instead, FTP communications may not work
correctly. Note also that TCP port 21 is the standard port number for FTP. Finally,
the use of port ranges for FTP forwarding is not supported; a port count of 1 is
required.
Example
For example, to enable port forwarding of RealPort data (network port 771) on a Digi Connect
WAN VPN to a Digi Connect SP with an IP address of 10.8.128.10, you would do the following:
 Make sure the Enable IP Routing checkbox is checked.
 In the Forward TCP/UDP connections from external networks to the following
internal devices section, enter the port forwarding information as follows, and click
Add: