ZyXEL Communications eir F1000 - NAT Application

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eir F1000 Modem User’s Guide
Chapter 9 Network Address Translation (NAT)
9.9.4 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 95 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 66 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