User guide

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DSU ProxyServer User Guide
MTPSR2-201
Enabling Virtual Servers
The virtual server feature of the ProxyServer enables you to have multiple servers on your local area
network (LAN) with one static IP address. A normal Internet connection requires a static IP address
for each server on your LAN. A normal Internet connection is shown in Figure 4-4.
Internet
Hub
Web Server
204.111.2.30
FTP Server
204.111.2.20
Router
Secure
LAN
Firewall
204.111.2.60
RD
TD
CL
LK
RD TD CD NS DS RD TD CD
V35
Figure 4-4. Normal Internet Connection for ProxyServer
In a normal Internet connection with a router connected to the Internet, you need a static IP address
for each function (server) you want to perform on the Internet. For example, for a Web server to
browse the Internet, it needs an IP address so the router knows where the traffic is coming from and
where to send the reply. In our normal Internet connection we have assigned the address
204.111.2.30 to the Web server, address 204.111.2.20 to the FTP server, and 204.111.2.60 to the
Firewall ProxyServer.
To reduce the number of static IP addresses, a virtual server feature is present in the ProxyServer
that enables you to map multiple local servers to a single static IP address or to a Global Dynamic
WAN port address. The virtual server feature enables the ProxyServer to take requests from
different servers (functions) and interact with the Internet based on the functionality of each request.
In the normal Internet connection, this was a physical linkage to a specific IP address. The virtual
server feature is a functional connection. Functionality is defined by how the server is used; e.g., the
Web server uses a www-http protocol, and an e-mail server uses pop-3 and SMTP protocol.
Therefore, multiple requests can be sent to the Internet over a single physical connection and the
ProxyServer will know which server is requesting service.
The following example, shown in Figure 4-5, shows a DSU ProxyServer connected to the Internet
with a single static IP address or Global Dynamic WAN port address and the same servers used in
the previous example are now connected to the Internet through the ProxyServer.
If instead of mapping a static IP address from your ISP to the ProxyServer, you employed Multi-
Tech’s Global Dynamic WAN port addressing method, you no longer have to be concerned with a
single static IP address from your ISP. You can assign a predefined Global Dynamic WAN port
address to each of the ProxyServer’s WAN ports and then map your servers to those WAN port