"IPCop offers an interesting interface that provides you with
detailed information about what kind of attacks are currently
active on your network. This information is provided as an
integration with Snort, a project that focuses on discovering
intrusion attempts. In order to access this information open IPCop,
select the Services Tab and Intrusion Detection System
Administration. This will open up a page that will allow you to
configure the Snort rules.
"The first option you will have is to choose which interfaces to
use Snort rules on. In the example a Red Zone, the Internet facing
network card and the Green Zone, the internal network are both
checked..."