CentOS is just like Red Hat, but without the price tag and with the virtuous license. When belts have to be tightened, we want to read about an OS with all the features of a commercial Linux variety, but without the pain. The Definitive Guide to CentOS is the first definitive reference for CentOS and focuses on CentOS alone, the workhorse Linux distribution, that does the heavy lifting in small and medium-size enterprises without drawing too much attention to itself. Provides tutorial and hands-on learning but is also designed to be used as a reference Bases all examples on real-world tasks that readers are likely to perform Serves up hard-won examples and hints and tips from the author's experiences of CentOS in production

Design a complete VoIP or analog PBX with Asterisk, even if you have no previous Asterisk experience and only basic telecommunications knowledge. This bestselling guide makes it easy, with a detailed roadmap to installing, configuring, and integrating this open source software into your existing phone system. Ideal for Linux administrators, developers, and power users, this book shows you how to write a basic dialplan step by step, and quickly brings you up to speed on the latest Asterisk features in version 1.8. Integrate Asterisk with analog, VoIP, and digital telephony systems Build a simple interactive dialplan, and dive into advanced concepts Use Asterisk’s voicemail options—including a standalone voicemail server Build a menuing system and add applications that act on caller input Incorporate a relational database with MySQL and Postgre SQL Connect to external services such as LDAP, calendars, XMPP, and Skype Use Automatic Call Distribution to build a call queuing system Learn how to use Asterisk’s security, call routing, and faxing features

A unique, full-color introduction to Linux fundamentals Serving as a low-cost, secure alternative to expensive operating systems, Linux is a UNIX-based, open source operating system. Full-color and concise, this beginner's guide takes a learning-by-doing approach to understanding the essentials of Linux. Each chapter begins by clearly identifying what you will learn in the chapter, followed by a straightforward discussion of concepts that leads you right into hands-on tutorials. Chapters conclude with additional exercises and review questions, allowing you to reinforce and measure your understanding. Offers a hands-on approach to acquiring a foundation of Linux skills, aiming to ensure Linux beginners gain a solid understanding Uses the leading Linux distribution Fedora to demonstrate tutorials and examples Addresses Linux installation, desktop configuration, management of files and filesystems, remote administration, security, and more This book is essential reading for anyone entering the world of Linux!

This guide readers from the basic configuration to the full power of Postfix. It discusses the interfaces to various tools that round out a fully scalable and highly secure email system. These tools include POP, IMAP, LDAP, MySQL, Simple Authentication and Security Layer (SASL), and Transport Layer Security (TLS, an upgrade of SSL).

Arguably one of the most highly regarded and widely used enterprise level operating systems available today is the CentOS 8 distribution. Not only is it considered to be among the most stable and reliable operating systems, it is also backed by the considerable resources and technical skills of Red Hat, Inc. CentOS 8 Essentials is designed to provide detailed information on the installation, use and administration of the CentOS 8 distribution. For beginners, the book covers topics such as operating system installation, the basics of the GNOME desktop environment, configuring email and web servers and installing packages and system updates using App Streams. Additional installation topics such as dual booting with Microsoft Windows are also covered, together with all important security topics such as configuring a firewall and user and group administration. For the experienced user, topics such as remote desktop access, the Cockpit web interface, logical volume management (LVM), disk partitioning, swap management, KVM virtualization, Secure Shell (SSH), Linux Containers and file sharing using both Samba and NFS are covered in detail to provide a thorough overview of this enterprise class operating system.

Design a complete Voice over IP (VoIP) or traditional PBX system with Asterisk, even if you have only basic telecommunications knowledge. This bestselling guide makes it easy with a detailed roadmap that shows you how to install and configure this open source software, whether you’re upgrading your existing phone system or starting from scratch. Ideal for Linux administrators, developers, and power users, this updated fifth edition shows you how to set up VoIP-based private telephone switching systems within the enterprise. You’ll get up to speed on the features in Asterisk 16, the latest long-term support release from Digium. This book also includes new chapters on WebRTC and the Asterisk Real-time Interface (ARI). Discover how WebRTC provides a new direction for Asterisk Gain the knowledge to build a simple but complete phone system Build an interactive dialplan, using best practices for Asterisk’s advanced features Learn how ARI has emerged as the API of choice for interfacing web development languages with Asterisk

Design a complete Voice over IP (VoIP) or traditional PBX system with Asterisk, even if you have only basic telecommunications knowledge. This bestselling guide makes it easy, with a detailed roadmap that shows you how to install and configure this open source software, whether you’re upgrading your existing phone system or starting from scratch. Ideal for Linux administrators, developers, and power users, this updated edition shows you how to write a basic dialplan step-by-step, and brings you up to speed on the features in Asterisk 11, the latest long-term support release from Digium. You’ll quickly gain working knowledge to build a simple yet inclusive system. Integrate Asterisk with analog, VoIP, and digital telephony systems Build an interactive dialplan, using best practices for more advanced features Delve into voicemail options, such as storing messages in a database Connect to external services including Google Talk, XMPP, and calendars Incorporate Asterisk features and functions into a relational database to facilitate information sharing Learn how to use Asterisk’s security, call routing, and faxing features Monitor and control your system with the Asterisk Manager Interface (AMI) Plan for expansion by learning tools for building distributed systems