This new edition of Practical UNIX and Internet Security provides detailed coverage of modern security and networking issues. It focuses on the four most popular Unix variants: Solaris, Linux, FreeBSD, and Mac OS X. It covers: computer security basics - introduction to security problems and solutions, Unix history and lineage, and the importance of security policies as a basic element of system security; security building blocks: fundamentals of Unix passwords, users, groups, the Unix file system, cryptography, physical security, and personnel security; network security - a detailed look at modem and dialup security, TCP/IP, securing individual network services, Sun's RPC, various host and network authentication systems (e.g., NIS, NIS+, and Kerberos), NFS and other file systems, and the importance of secure programming; secure operations - keeping up to date in today's changing security world, backups, defending against attacks, performing integrity management, and auditing; and incidents - discovering a break-in, dealing with programmed threats and denial of service attacks, and legal aspects of computer security. The book also includes a variety of helpful appendixes, including a comprehensive security checklist and a detailed bibliography of paper and electronic references for further reading and research. In addition to bringing the entire book up to date, the authors have added far more information about Linux, security policy, and cryptography, and have added new sections on embedded systems, biometrics, additional Internet protocols, new authentication systems such as LDAP and PAM, and anti-theft technologies. Packed with 1000 pages of helpful text, scripts, tips, and warnings, this third edition should be a useful reference for Unix administrators and anyone concerned about keeping their systems and networks secure.