User`s guide

equivalent of the hex data. This is the section that lets you actually peer into

the packet and see what type of data is being transmitted, character-by-character.

3.2.4.3 Configuration

Using Ethereal can be as simple as you want it to be. By default it comes with everything set

up for full sniffing, and the only necessary setting is the selection of the network interface

device. However, because of a very user-friendly user interface, this option is simple to use and

easy to find.

To start sniffing, ensure that you have a network card in operational mode. This means the

NIC’s drivers must be installed and the card must be able to receive and transmit data. If the

card does not work properly before using Ethereal, it will certainly not work while it is running.

In addition, if you are using a WNIC, you might be limited as to how far out on the network you

can sniff. If you are using a *nix OS, you will probably be able to sniff to at least the wireless

router, wireless access point, or closest switch. If you are using Windows, your WNIC will only

capture local data. Keep this in mind, or else you will spend hours attempting to troubleshoot a

known issue.

To set up Ethereal to use your NIC, click Capture → Start. You will be shown a screen

similar to Figure 9.2.