SCNM packet capture deamon only works with FreeBSD. The client-side tools all work with any Unix system.
Download the SCNM source code or binaries here http://dsd.lbl.gov/OldProjects/SCNM/download/
After getting the tar file, follow the instructions in the file README.txt to build and install the software. Please note the LICENSE.txt file in the top-level directory, explaining the terms of use of the software.