Chapter 12 Network Address Translation (NAT)
12.8.4 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 74 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 52 Services and Port Numbers
SERVICES | PORT NUMBER |
ECHO | 7 |
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FTP (File Transfer Protocol) | 21 |
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SMTP (Simple Mail Transfer Protocol) | 25 |
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DNS (Domain Name System) | 53 |
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Finger | 79 |
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HTTP (Hyper Text Transfer protocol or WWW, Web) | 80 |
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POP3 (Post Office Protocol) | 110 |
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NNTP (Network News Transport Protocol) | 119 |
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SNMP (Simple Network Management Protocol) | 161 |
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190 |
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