ZyXEL Communications 660HW Series - Manual (Page 120)

Prestige 660H/HW Series User’s Guide
119 Chapter 9 Network Address Translation (NAT) Screens
9.3.3 Configuring Servers Behind SUA (Example)
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
9.4 SIP ALG
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)
SERVICES PORT NUMBER