User`s manual

P-660 Series Support Notes
50
All contents copyright © 2005 ZyXEL Communications Corporation.
Press ENTER to Confirm or ESC to Cancel:
The most often used port numbers are shown in the following table. Please refer RFC
1700 for further information about port numbers.
Service Port Number
FTP 21
Telnet 23
SMTP 25
DNS (Domain Name Server) 53
www-http (Web) 80
PPTP (Point-to-Point Tunneling
Protocol)
1723
Examples
• Internet Access Only
• Internet Access with an Internal Server
• Using Multiple Global IP addresses for clients and servers
• Support Non NAT Friendly Applications
1. Internet Access Only
In our Internet Access example, we only need one rule where all our ILAs map to one
IGA assigned by the ISP. See the following figure.