jpckt32 will provide a Java interface that will enable developers to write network layer applications, such as a traffic analyzer.  The interface will be event driven and will include packet filtering, protocol recognition, and packet manipulation.  jpckt32 uses the Java Native Interface (JNI) to make calls to libpcap (low level packet trapping/filtering) and libnet (protocol recognition/manipulation). 

Download and install libpcap.

Download and install libnet libnet.

Download jpckt32.