ZyXEL Communications Corporation VMG1312B10C Manuel D’Utilisation

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Chapter 10 Network Address Translation (NAT)
VMG1312-B10C User’s Guide
164
10.8.4  NAT Application
The following figure illustrates a possible NAT application, where three inside LANs (logical LANs 
using IP alias) behind the Device can communicate with three distinct WAN networks.
Figure 86   
NAT Application With IP Alias
Port Forwarding: Services and Port Numbers
The most often used port numbers are shown in the following table. Please refer to RFC 1700 for 
further information about port numbers. Please also refer to the Supporting CD for more examples 
and details on port forwarding and NAT.
Table 64   
Services and Port Numbers
SERVICES
PORT NUMBER
ECHO
7
FTP (File Transfer Protocol)
21
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