SMC Networks SMC7401BRA Network Router User Manual


 
Configuring Network Address Translation
76
You can specify a range using the [From/To] fields if you want
the rule to apply to a range of port types, or enter the same
port number in both fields.
A port ID identifies the specific function of the computer
connected to it, and therefore can limit the types of data
that pass to and from the computer.
For example, Web (HTTP) servers are usually identified
by port number 80; packets containing traffic destined for
a Web server will contain this port ID. The Internet Assigned
Numbers Authority (IANA) assigns port numbers for common
types of servers and functions.
7. If the LAN computer that you are making publicly available
is configured to use a non-standard port number for the type
of traffic it receives, type the non-standard port number in the
[Local Port:] field.
This option translates the standard port number in packets
destined for your LAN computer to the non-standard number
you specify. For example, if your Web server uses (non-
standard) port 2000, but you expect incoming data packets
to refer to (standard) port 80, you should enter 2000 here
(and select HTTP or type 80 in the Destination Port fields).
The headers of incoming packets destined for port 80 will
be modified to refer to port 2000. The packet will then be
routed appropriately to the web server.
8. Follow steps 8-12 under The NAPT Rule on page 70
to submit your changes.