Using EtherApe

EtherApe can be used to have an overview of traffic conditions in your network. It is a great tool to easily pinpoint who is consuming the most bandwith, or to check which computers are actually talking to some others.

Quick Start

Most of the time you will want to run EtherApe with root permissions in order to monitor a live network. If you are not the administrator of the machine running EtherApe , you will ony be able to analyze previously generated capture files, generated by someone else.

Starting EtherApe opens the Main window, shown in Figure 1.

Figure 1. EtherApe Main Window

By default, EtherApe will try to open the default network interface for capture in IP mode, and will display a diagram of network traffic right away.

Every computer currently taking part in a conversation in the network will be represented as a circle (a node) in the diagram, with its name displayed on top of it. The fact that two computers are communicating with each other is represented with a line between those two nodes (a link).

You will notice that both nodes and links vary with time in color and size. Size is used to represent the amount of traffic: The bigger a node is, the more traffic it is dumping into the network. The wider a link is, the more data is flowing in that particular between those two nodes.

Color, on the other hand, is used to represent the protocol being used the most by a link or a node. You will find a legend for what a particular color means in the left side of the main window.

Look closely and you will notice that in fact links are not lines between nodes. Rather, every direction of communication is represented by a triangle. Packets go from the shorter side to the opposite vertex. Since computers usally talk back, there will usually be two such triangles between two nodes, the base of each representing how much each node is contributing to the conversation.

You don't need to know much more if you just want to have a simple look at your network. Nevertheless, there are many settings that you can use to configure what exactly will appear in the diagram, and you will have to understand how this settings affect the program to have a proper comprehension of the meaning of the display.

Besides, EtherApe offers you the possibility of displaying stastistics for many of the elements involved. Read on to learn how.

EtherApe Main Window

The main window is composed of five different elements:

The Menu Bar

The menu bar

Proving a Theorem

To get a proof of a theorem, select File->New, which will bring up the New Proof dialog box. Enter the statement of the theorem in the Theorem statement field, select your desired proof type from the drop-down menu, and and press Prove!.

If EtherApe cannot prove the theorem by the method you have chosen, or if you have not selected a proof type at all, EtherApe will attempt to choose the one that it thinks is most conclusive. In order, it will attempt to prove the theorem with the following techniques:

Deduction

This is a proof method that is generally accepted for full credit by Logic professors.

Induction

This logical style will also earn you full credit on your homework.

Dialog

This logical method is best for Philosophy classes, and will probably only merit partial credit on Logic or Mathematics homework.

Confusion

Suitable only for political debates, battles of wits against the unarmed, and Philosophy classes focusing on the works of Kant. Use with caution.

WarningProving Incorrect Theorms
 

EtherApe cannot prove incorrect theorems. If the theorem you have entered is not demonstrably true, you will get a message to that effect in the main window. To disprove a theorem, ask EtherApe to prove its logical inverse.

Editing Proofs

Once you have proven the theorem, it will be displayed in the main window. There, you can read it over, choose text styles for different portions of it, and make comments on it. This section will guide you through that process.

To alter text styles, first select the statement you wish to change by clicking on it once. You can select several statements by Then, choose the style you want to apply from the Style submenu of the Edit menu. EtherApe will convert the text to that style.

You can also enter comments on a statement by selecting that statement, and then beginning to type. Comments will appear after the statement you have selected.

NoteAltering The Proofs Themselves
 

EtherApe does not allow you to alter a proof it has produced itself. You can, save your proof as a plain text file (using the Save as... menu), and alter it that way. Be aware, however, that EtherApe uses its own file format for saved proofs, and cannot re-open a file unless it is in the .mga format.

Toolbar

The toolbar (shown in Figure 2) provides access to several commonly used routines.

Figure 2. EtherApe Toolbar

New

Brings up the New Theorem dialog.

Open

Open an exisiting theorem you want to prove, or a completed proof you wish to print or format.

Save

Save the current theorem permanently in a file.

Menus

The menu bar, located at the top of the Main Window, contains the following menus:

File

This menu contains:

  • Open (F3) — This opens a file which is saved on your computer.

  • Save (Ctrl-S) — This saves your file.

  • Close (Ctrl-W) — This closes your file.

  • Exit (Ctrl-Q) — This quits the application.

Edit

This menu contains:

  • Cut (Ctrl-X) — This removes any text or data which is selected and places it in the buffer.

  • Copy (Ctrl-C) — This copies any text or data which is selected into the buffer.

  • Paste (Ctrl-V) — This pastes any text or data which is copied into the buffer.

  • COMMAND1… — This opens the COMMAND1 dialog, which is used to ....

  • COMMAND2 — This ....

Settings

This menu contains:

  • Preferences… — This opens the Preferences Dialog, which allows you to configure many settings.

  • COMMAND3 — This command does something.

Help

This menu contains:

  • Manual — This opens the GNOME Help Browser and displays this manual.

  • About — This opens the About dialog which shows basic information about EtherApe, such as the author's name, the application version number, and the URL for the application's Web page if one exists.