Practical Unix & Internet Security
is on its second edition, and its maturity shows. To call this highly readable book comprehensive is an understatement. The breadth is vast, from fundamentals (definitions of computer security; the history of Unix) and commonsense but little-observed security basics (making backups; physical and personnel security; buggy software) to modern software (NFS, WWW, firewalls) and the handling of security incidents. The section on users and passwords alone is 21 pages long--and worth every page. Useful appendices include a Unix security checklist, a list of emergency response organizations, and many references to electronic and paper resources.
The Internet covers too much and moves too quickly for any book to cover every security aspect of every piece of software, but this book comes close. More importantly, it gives you an exceptional grounding in the fundamental issues of security and teaches the right questions to ask--something that will stay with you long after today's software is obsolete.
"It's almost impossible to criticize such a venerable work as this, and there can be little doubt that backed up by online resources, this will form a solid foundation and reference work for years to come." - Martin Howse, LinuxUser & Developer, Issue 30 "If you know nothing about Linux security, and only have time for one book, you should start with Practical Unix and Internet Security." - Charlie Stross, Linux Format, September