ZyXEL Communications P-2302R Series User Manual
P-2302R Series User’s Guide
Chapter 12 Network Address Translation (NAT) Screens
132
You may enter a single port number or a range of port numbers to be forwarded, and the local
IP address of the desired server. The port number identifies a service; for example, web
service is on port 80 and FTP on port 21. In some cases, such as for unknown services or
where one server can support more than one service (for example both FTP and web service),
it might be better to specify a range of port numbers. You can allocate a server IP address that
corresponds to a port or a range of ports.
IP address of the desired server. The port number identifies a service; for example, web
service is on port 80 and FTP on port 21. In some cases, such as for unknown services or
where one server can support more than one service (for example both FTP and web service),
it might be better to specify a range of port numbers. You can allocate a server IP address that
corresponds to a port or a range of ports.
Note: Many residential broadband ISP accounts do not allow you to run any server
processes (such as a Web or FTP server) from your location. Your ISP may
periodically check for servers and may suspend your account if it discovers any
active services at your location. If you are unsure, refer to your ISP.
periodically check for servers and may suspend your account if it discovers any
active services at your location. If you are unsure, refer to your ISP.
12.3.1 Default Server IP Address
In addition to the servers for specified services, NAT supports a default server IP address. A
default server receives packets from ports that are not specified in this screen
default server receives packets from ports that are not specified in this screen
Note: If you do not assign a default server IP address, the Prestige discards all
packets received for ports that are not specified in this screen or remote
management.
management.
12.3.2 Port Forwarding: Services and Port Numbers
A NAT server set is a list of inside (behind NAT on the LAN) servers, for example, web or
FTP, that you can make accessible to the outside world even though NAT makes your whole
inside network appear as a single machine to the outside world.
FTP, that you can make accessible to the outside world even though NAT makes your whole
inside network appear as a single machine to the outside world.
Use the SUA Server page to forward incoming service requests to the server(s) on your local
network. You may enter a single port number or a range of port numbers to be forwarded, and
the local IP address of the desired server. The port number identifies a service; for example,
web service is on port 80 and FTP on port 21. In some cases, such as for unknown services or
where one server can support more than one service (for example both FTP and web service),
it might be better to specify a range of port numbers.
network. You may enter a single port number or a range of port numbers to be forwarded, and
the local IP address of the desired server. The port number identifies a service; for example,
web service is on port 80 and FTP on port 21. In some cases, such as for unknown services or
where one server can support more than one service (for example both FTP and web service),
it might be better to specify a range of port numbers.
In addition to the servers for specified services, NAT supports a default server. A service
request that does not have a server explicitly designated for it is forwarded to the default
server. If the default is not defined, the service request is simply discarded.
request that does not have a server explicitly designated for it is forwarded to the default
server. If the default is not defined, the service request is simply discarded.
The most often used port numbers are shown in the following table. Please refer to RFC 1700
for further information about port numbers. Please also refer to the Supporting CD for more
examples and details on SUA/NAT.
for further information about port numbers. Please also refer to the Supporting CD for more
examples and details on SUA/NAT.
Table 34 Services and Port Numbers
SERVICES
PORT NUMBER
ECHO
7
FTP (File Transfer Protocol)
21
SMTP (Simple Mail Transfer Protocol)
25