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addition, you can also configure a server, e.g., a Web server, on
your local network and make it accessible by outside users.
If you do not set a server IP address, SUA offers the additional
benefit of firewall protection. This is because if no server is defined,
all incoming inquiries will be filtered out by the router even if you
do have a server on your network. This can prevent intruders from
probing your system.
The router 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
translation, refer to RFC 1631, The IP Network Address Translator
(NAT).
In summary:
1. SUA is an ideal, cost-effective solution for small offices with
less than 20 hosts using a LAN to concurrently access the
Internet or other remote TCP/IP network.
2. SUA can provide one server address to be accessed by
Remote Dial-in Users, thus controlling the incoming packets.
3. SUA can provide firewall protection if you do not configure a
server IP address. All incoming inquiries will be filtered out
by the DI-300 or DI-300M. Therefore, servers on your
network are protected.
4. UDP and TCP datagrams can be routed. In addition, ICMP
echo can also be routed.
The figure below shows an example of a small office connected to
the Internet via a Single User Account using a DI-300 or DI-300M.
Note that if you enable the Single User Account feature, your local
44
Configuring for Internet Access
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