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DI-206 ISDN Remote Router
The parameters are described as follows:
Global IP – This is a single, global IP Address that is valid on the Internet, or on
the same subnet of the global interface.
Local IP – This is a single, local IP Address that is not valid on the Internet.
State – Enables or disables this entry.
Static NAPT
This screen (below) is how the NAT IP Pool appears, if Static NAPT was chosen for
the Translation Mode parameter. Each entry in this configuration can be used to map
a global address and port to a local address and port. Notice that the global address
will be the external IP address of the global interface.
The parameter not explained in the previous sections is described as follows:
Port – This is a destination port number used by TCP and UDP to de-multiplex
incoming IP packets.
In the above example, incoming packets with the global destination IP Address
(211.11.22.3) and global destination TCP/UDP port (21) will be translated to a
packet with the local destination IP Address (1.1.1.5) and local TCP/UDP port (21).
Port 21 is assigned to FTP servers. Please see Appendix D for more commonly
assigned port numbers, or RFC 1700 for a more complete list.
Configure NAPT for Special Aps
Some applications programs that are used over the Internet such as Microsoft
NetMeeting, Diablo, CU See Me and Xwindows send information to a certain port
number or within a specified range of port numbers. The exact port number used is
specific to the application. However, if you find that you are having trouble using an
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