The authors believe that providing security for supercomputer clusters is different from providing security for stand-alone PCs. The types of programs that supercomputer clusters run and the sort of data available on supercomputer clusters are fundamentally different from the programs and data found on stand-alone PCs. This situation might attract a different type of attacker with different goals and different tactics. This paper discusses the results of a questionnaire sent out to many supercomputer clusters in the United States and relates them to a literature search that was also undertaken. These results suggest approaches that can be taken to further secure supercomputer clusters.