Airlink RTW026 - Manual (Page 55)

Chapter 4: Web Configuration
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Virtual Server Configuration
The Router implements NAT to let your entire local network appear as a single machine to the Internet. The typical
situation is that you have local servers for different services and you want to make them publicly accessible. With
NAT applied, it will translate the internal IP addresses of these servers to a single IP address that is unique on the
Internet. NAT function not only eliminates the need for multiple public IP addresses but also provides a measure of
security for your LAN.
When the router receives an incoming IP packet requesting for access to your local server, the router will recognize
the service type according to the port number in this packet (e.g., port 80 indicates HTTP service and port 21
indicates FTP service). By specifying the port number, you tell the router which service should be forwarded to the
local IP address you specify.
After you setting the virtual server you should modify the filter rule whichever port and service you set on virtual
server. Because the firewall has protected the route by filter rule so that you should update the filter rule after you set
up virtual server.
Virtual Server allows you to make servers on your LAN accessible to Internet users. Normally, Internet users would
not be able to access a server on your LAN because:
!"
You server does not have a valid external IP Address.
!"
Attempts to connect to devices on your LAN are blocked by the firewall in this device.
The Virtual Server feature solves these problems and allows Internet users to connect to your servers, as illustrated
below:
(192.168.1.10)
(192.168.1.254)
(192.168.1.20)
IP Address seen by Internet Users
Please note that, in the above picture, both Internet users are connecting to the same IP address, but using different
protocols.
To Internet users, all virtual servers on your LAN have the same IP Address. This IP Address is allocated by your ISP.
This address should be static, rather then dynamic, to make it easier for Internet users to connect to your Servers.
However, you can use Dynamic DNS feature to allow users to connect to your virtual servers by using a URL,
instead of an IP address.