Nat Application - ZyXEL Communications P-660HN-51 - V1.10 Manual

Chapter 8 Network Address Translation (NAT)

8.8.4 NAT Application

The following figure illustrates a possible NAT application, where three inside LANs
(logical LANs using IP alias) behind the ZyXEL Device can communicate with three
distinct WAN networks.
Figure 54 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 37 Services and Port Numbers
SERVICES
ECHO
FTP (File Transfer Protocol)
SMTP (Simple Mail Transfer Protocol)
DNS (Domain Name System)
Finger
HTTP (Hyper Text Transfer protocol or WWW, Web)
POP3 (Post Office Protocol)
NNTP (Network News Transport Protocol)
SNMP (Simple Network Management Protocol)
148
PORT NUMBER
7
21
25
53
79
80
110
119
161
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