We'll start by describing many good things that you (or someone in your organization) ought to be doing.
You'll notice, we expect, that the following lists read largely like texts on how to secure an operating system or network. They are indeed a start in that direction. We don't want to leave the impression, however, that our lists are comprehensive. We invite you to read more detailed descriptions of how to secure your operating system separately. After all, many of the elements that we cite can—and have—been turned into entire volumes by themselves! 
 A more complete list of books and documents are available in Appendix A, but some of the best known ones on the subject of Unix are Practical Unix & Internet Security (now in its third edition) by Simson Garfinkel, Gene Spafford, and Alan Schwartz, as well as the Unix Security Checklist from AusCERT (www.auscert.org.au/).
Still, these lists (which are directly derived from our experiences in assessing business applications) should stand you in good stead. We've layered the principles, starting with guidelines for networks and progressing up through operations procedures. (Figure 5-2 shows the layers more graphically.) One caution, however: make sure to consider the list as whole, and don't get caught in the trap of thinking that only one aspect of security is relevant to your job function.
The security ...