This book is based on Red Hat® Enterprise Linux 5 (RHEL 5) and is intended for individuals who plan to take the new Red Hat® Certified Technician (RH202) and/or Red Hat® Certified Engineer (RH302) exams and pass them, want to use it as a quick on-the-job resource or like to learn RHEL from the beginning in an easy-to-understand way.The book has 31 chapters and facilitates readers to grasp concepts, understand implementation procedures, learn command syntax, configuration files and daemons involved, and comprehend troubleshooting. The chapters are divided into four areas: Linux Essentials, RHEL System Administration, RHEL Network and Security Administration, and RHEL Troubleshooting.01. Linux Essentials (Chapters 1 to 7) covers the basics of Linux. Information provided includes general Linux concepts, basic commands, file manipulation and file security techniques, text file editors, shell features, basic shell and awk programming and other essential topics. These chapters are good for gaining an overall understanding of Linux and cover common skills useful for both exams.02. RHEL System Administration (Chapters 8 to 19) covers system administration concepts and topics including hardware management, local installation, X Window and desktop managers, software and user/group account administration, disk partitioning using standard, RAID and LVM, file system and swap management, system shutdown and boot procedures, kernel management, backup, restore and compression functions, print services administration, and automation and system logging. These chapters cover objectives outlined for the RH202 exam.03. RHEL Network and Security Administration (Chapters 20 to 30) covers network and security administration concepts and topics such as OSI and TCP/IP reference models, subnetting and IP aliasing, network interface administration, routing, basic network testing and troubleshooting tools, naming services (DNS, NIS, LDAP) and DHCP; Internet services and electronic mail management, time synchronization with NTP, resource sharing with NFS, AutoFS and Samba, network-based and hands-free automated installation, Apache web server and Squid caching/proxy server, secure shell, PAM, TCP Wrappers, IPTables, NATting, SELinux and recommendations for system hardening. These chapters cover objectives set for the RH302 exam.04. RHEL Troubleshooting (Chapter 31) covers a number of sample system, network and security troubleshooting scenarios. This chapter covers objectives related to diagnoses and troubleshooting for both exams.The book covers ALL official exam objectives and includes several exercises for exam practice. This book is not a replacement for RHCT®/RHCE® training courses offered by Red Hat, Inc., but may be used to prepare for both the exams. The information contained in this book is not endorsed by Red Hat, Inc.Good Luck on the exams .........