ZyXEL Communications P-660RU-Tx 用户手册

 Chapter 10 Network Address Translation (NAT)

P-660RU-Tx User’s Guide

The most often used port numbers and services are shown in 

. Please refer to RFC 1700 for further information about port numbers. 

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.

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 example). You assign the LAN IP 
addresses and the ISP assigns the WAN IP address. The NAT network appears as a 
single host on the Internet.

Figure 36   Multiple Servers Behind NAT Example

The following table summarizes the settings described in the above example.

Table 23   Multiple Servers Behind NAT Example

A

FTP

21-22

192.168.1.33

B

Telnet

23

192.168.1.34

C

SMTP

25

192.168.1.35

A=192.168.1.33

C=192.168.1.35

B=192.168.1.34