Zyxel NBG-418N v2 - Инструкция по эксплуатации - Страница 109

 Chapter 10 Network Address Translation

NBG-418N v2 User’s Guide

109

1 0 .6   Te 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.

1 0 .6 .1   NA T Po rt Fo rwa rd ing : 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. 

Use the 

A p p lic a tio n 

screen 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.

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.

1 0 .6 .2   NA T Po rt Fo rwa rd ing  Exa m p le

Let's say you want to assign ports 21-25 to one FTP, Telnet and SMTP server (

A

 in the example), port 80 to 

another (

B

 in the example) and assign a default server IP address of 192.168.1.35 to a third (

C

 in the 

Apply

Click 

A p p ly

 to save your changes back to the NBG-418N v2.

Reset

Click 

Re se t

 to begin configuring this screen afresh.

Application Rules Summary

Service Name

This field displays the name of the application rule.

Trigger Protocol

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.

Direction

This field displays the direction of travel of packets that match this rule.

Match Port

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.

Open Protocol

This field displays the protocol a server on the WAN uses when it sends out a particular service. 

Related Port

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. 

Action

Click 

De le te

 to remove the rule.

Table 50   Network > NAT > Port Triggering (continued)

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