ZyXEL ADSL Router Prestige 660H-63 130122.G0660H63 Betriebsanweisung

Prestige 660H/HW Series User’s Guide

119 

Chapter 9 Network Address Translation (NAT) Screens

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.

IP address assigned by ISP.

Figure 50   Multiple Servers Behind NAT Example

The Prestige is a SIP Application Layer Gateway (ALG). A SIP ALG allows VoIP calls to 
pass through NAT by examining and translating IP addresses embedded in the data stream. 
When a VoIP device behind the Prestige registers with the SIP register server, the Prestige 
translates the device’s private IP address inside the SIP data stream to a public IP address. You 
do not need to use STUN with a VoIP device that is behind the Prestige.

SMTP (Simple Mail Transfer Protocol)

25

DNS (Domain Name System)

53

Finger

79

HTTP (Hyper Text Transfer protocol or WWW, Web)

80

POP3 (Post Office Protocol)

110

NNTP (Network News Transport Protocol)

119

SNMP (Simple Network Management Protocol)

161

SNMP trap

162

PPTP (Point-to-Point Tunneling Protocol)

1723

Table 29   Services and Port Numbers (continued)