Prestige 100MH PSTN Router/Hub
3-10
Chapter 3
Internet Access Application
The Single User Account feature may also be used to connect to remote networks other than
the Internet. For example, this feature can be used to simplify the allocation of IP addresses
when connecting branch offices to the corporate network.
The IP address for the SUA can be either fixed or dynamically assigned by the ISP (or another
remote node). In addition, you can also configure a server (for example, a Web server) on
your local network and make it accessible by outside users. When a server has been defined,
all connections initiated from the outside are being sent to that server. Thus, in order to telnet
to the
Prestige
you will first need to telnet to the server by using the outside address, and then
connect from the server to the
Prestige
by using the
Prestige
’s inside IP address.
If you do not set a server IP address, SUA offers the additional benefit of firewall protection.
With SUA, all incoming inquiries will be filtered out by your
Prestige
even if no server is
defined. This can prevent intruders from probing your system.
Your
Prestige
accomplishes this address sharing by translating the internal LAN IP addresses
to a single address that is globally unique on the Internet. For more information on IP address
transla tion, refer to RFC 1631,
The IP Network Address Translator (NAT)
.
3.5.1 Advantages of SUA
The advantages of SUA include
l
SUA is an ideal cost-effective solution for small offices with a few tens of hosts to
concurrently access the Internet or other remote TCP/IP network.
l
SUA can provide a single server address to be accessed by the outside world.
l
SUA can provide firewall protection if you do not configure a server IP address. All
incoming inquiries will be filtered out by your
Prestige
, protecting your network.
l
UDP and TCP datagrams can be routed. In addition, partial ICMP is supported.
Figure 3-5 above shows an example of a small office connected to the Internet via a SUA.