Technical Reference; Nat Port Forwarding: Services And Port Numbers; Nat Port Forwarding Example - ZyXEL Communications NBG-418N v2 User Manual

Table 50 Network > NAT > Port Triggering (continued)
L ABEL
Apply
Reset
Application Rules Summary
Service Name
Trigger Protocol
Direction
Match Port
Open Protocol
Related Port
Action
10.6 T e c hnic a l Re fe re nc e
The following section contains additional technical information about the NBG-418N v2 features
described in this chapter.
10.6.1 NAT Po rt Fo rwa rding : Se rvic e s a nd Po rt Num b e rs
A port forwarding 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.
Applic a tio n
Use the
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.
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.
10.6.2 NAT Po rt Fo rwa rding Exa m ple
Let's say you want to assign ports 21-25 to one FTP, Telnet and SMTP server (
B
another ( in the example) and assign a default server IP address of 192.168.1.35 to a third (
Chapter 10 Network Address Translation
DESC RIPT IO N
Click Apply to save your changes back to the NBG-418N v2.
Click Re se t to begin configuring this screen afresh.
This field displays the name of the application rule.
This field displays the protocol that causes (or triggers) the NBG-418N v2 to record the IP
address of the LAN computer that sent the traffic to a server on the WAN.
This field displays the direction of travel of packets that match this rule.
This field displays the port(s) that causes (or triggers) the NBG-418N v2 to record the IP address
of the LAN computer that sent the traffic to a server on the WAN.
This field displays the protocol a server on the WAN uses when it sends out a particular service.
This field displays the port(s) a server on the WAN uses when it sends out a particular service.
The EMG2926-Q10A forwards the traffic with this port (or range of ports) to the client computer
on the LAN that requested the service.
Click De le te to remove the rule.
screen to forward incoming service requests to the server(s) on your local network.
NBG-418N v2 User's Guide
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A in the example), port 80 to
C
in the