A typical use of GProxy is shown in the following picture
Suppose this is your LAN, you have only one connection to the
service provider through a single modem connected to one of the
four PCs of your LAN. Normally you can access the Internet only
from the PC that in the picture has address 192.168.0.1. The
other PCs in the LAN cannot access the Internet because, even if
they can exchange packets between them, 192.168.0.1 is unable to
route any packet from the LAN to the service provider and from
the service provider to the LAN. On the other hand, none of the
PCs in your LAN can be addressed from outside because the IP
addresses you used are only for your purposes and nobody assigned
exclusively them to you.
If you want to access the Internet from any of the other PCs
(192.168.0.2-3-4) you have to install GProxy in the PC
192.168.0.1.
If 192.168.0.3 is runnig an Internet browser and the user wants to access the URL http://www.uni.net/raimm/paolo/index.htm, the browser cannot ask directly the Internet for that page, it has to send the request for that page to GProxy at the address 192.168.0.1, then GProxy will send the http request to www.uni.net waiting for the page content (index.htm). While the page is sent back from www.uni.net to 192.168.0.1 data are forwarded through GProxy to 192.168.0.3 and the page is finally displayed in the browser running on it. In a few words, GProxy operates like a bridge between the Internet and your LAN. It is important to note that also the address 192.168.0.1 is not visible from the Internet: on the Internet side, your GProxy PC has the address that your service provider assigned to you (statically or dynamically).
We talked about IP address, we have also to spend a little word about "port number". Well, every PC connected to a LAN "listens" to the LAN using a different "ear" for each service, a kind of "channel"; HTTP service normally uses port 80, then GProxy normally uses port 80 for this service.
Then, using GProxy, the three PCs 192.168.0.2-3-4 can access the Internet, to do this you have to configure the browser on each PC so it can use a proxy server. This is a very simple operation. If you use Netscape, go to Options/Network preferences/Proxies and select “Manual proxy configuration”, then click “View” and write in “HTTP Proxy” the address of the PC of your LAN that runs GProxy (192.168.0.1), write also the port used that is 80. If you use IExplorer, go to View/Options/Connection and check "Connect through a proxy server", then click "Settings" and write in “HTTP” the address of the PC of your LAN that runs GProxy (192.168.0.xxx), and the port used that is 80.