ZyXEL Communications 202H - Manual (Page 119)

Prestige 202H User’s Guide
Dial-in Setup 11-13
In addition to the servers for specified services, NAT supports a default server. A service request that does
not have a server explicitly designated for it is forwarded to the default server. If the default is not defined,
the service request is simply discarded.
Many residential broadband ISP accounts do not allow you to run any server
processes (such as a Web or FTP server) from your location. Your ISP may
periodically check for servers and may suspend your account if it discovers any
active services at your location. If you are unsure, refer to your ISP.
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 included disk for more examples and details on
NAT.
Table 11-7 Services & Port Numbers
SERVICES PORT NUMBER
ECHO 7
FTP (File Transfer Protocol) 21
Telnet 23
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
11.4.1 Configuring a Server behind NAT
Follow these steps to configure a server behind NAT:
Step 1. Enter 15 in the main menu to go to Menu 15 - NAT Setup.