The Graphical User Interface (or GUI) is contained within a class named SimulationGUI.java. To start the GUI simply run the file named 'runGui.bat' (in Windows) included in the Release which will invoke the SimulationGUI class.
When the Java Firewall Simulator GUI starts a new window is open. Is divided in three areas. The left area, the central area, and the South area. The central area is the area where we draw nodes and lines. In the left area there are the node buttons for adding nodes(like nodes, routers, hubs, switchs). In the south area there are the function buttons(like the senario buttons, send, close).
Our first step in setting up a networking environment is to add some Nodes. Currently only 2 nodes are available, the PC Node and the Router Node.
To add PCs to our Simulation we click the pc icon on the left area of our window.
To add Routers to our Simulation we click the Router icon on the left area of our window.
Adding PCs
When the new PC window is displayed, we enter first the name of pc.
An interface is like an Network Interface Card(NIC). We have to put a name for that.
The IP address identifies a system’s location on the network in the same way a street address identifies a house on a city block. Just as a street address must identify a unique residence, an IP address must be unique.We have to put a number in the format "123.11.4.5" ; the numbers must be between 0 and 255.
We must fill all the fields correctly, otherwise the new PC is not added.
To add the new pc to the simulation click the add button.
Adding Routers
When the new Router window is displayed, we enter first the name of rourter.
We have to put a name for the new router.
A router could have more than one interface. We have to put the names of different interfaces and between them a space.
We have to put a different numbers in the format "123.11.4.5" ; the numbers must be between 0 and 255. The IP Addresses have to be the same number like the interfaces each one for the respectively interface divided by space.
We must fill all the fields correctly, otherwise the router is not added.
To add a link between two nodes and in the network simulation we have to click and select the respectively nodes.

When the new link window is displayed we put the name of the link. If there are free interfaces at the nodes they will be added to the link. If not, a message appeare telling you that there are no free interfaces to connect. Click the Add button to display the link.

To send data from one node to another simply click the send button to open the send data window. In the send data window choose a node from the combobox ; this is the sending node.

Put an IP Address for the receiving node.
Write a message name in the message name textfield.
In the message text Area write your message to send. When finish click on send.
The sending window now appears with the seven OSI layers.

When click the next layer button all the information about each layer is displayed in the respective text Areas.
On the top there is a box where we can see where the data are at every time.
If you click on the scenario1 button a preselected Network Simulation with two PCs and a Router is displayed.
The PCs are connected to the router and the simulation ready for use.
You can play with that.

If you click on the scenario2 button a more complex preselected Network Simulation with 4 PCs and 4 Routers is displayed.
The PCs are connected to the routers and the simulation ready for use.
You can play with that.

End. Enjoy!!!.