This book is designed as an Ubuntu 20.04 LTS Server administration and reference source, covering the Ubuntu servers and their support applications. Server tools are covered as well as the underlying configuration files and system implementations. The emphasis is on what administrators will need to know to perform key server support and management tasks. Coverage of the systemd service management system is integrated into the book. Topics covered include software management, systemd service management, systemd-networkd and Netplan network configuration, AppArmor security, OpenSSH, the Chrony time server, and Ubuntu cloud services. Key servers are examined, including Web, FTP, CUPS printing, NFS, and Samba Windows shares. Network support servers and applications covered include the Squid proxy server, the Domain Name System (BIND) server, DHCP, distributed network file systems, IPtables firewalls, and cloud computing. Part 1 focuses on basic tasks such as installing the Ubuntu Live Server, configuring networking with Netplan, systemd-networkd, and NetworkManager, managing software from the Ubuntu Snap and APT repositories, and basic usage for the desktop and the command line interfaces. Part 2 examines Internet servers as well as how services are managed by systemd using unit files. Configuration and implementation of the Postfix mail server, the vsftpd FTP server, the Apache Web server, as well as news and database servers are covered in detail. Part 3 deals with servers that provide shared resources on a local network or the Internet. Services examined include the CUPS printing server, NFS Linux network file server, and Samba Windows file and printing server, clustering, and cloud computing services supported by Ubuntu. Part 4 covers servers that provide network support, like the Squid proxy server, the Bind Domain Name System (DNS) server, DHCP servers, and the IPtables and FirewallD firewalls. Key networking operations are also examined like IPv6 auto-configuration, TPC/IP networking, and network monitoring tools. Part 5 provides a review of shell commands, including those used for managing files, as well as shell scripts, variables, and configuration files. The Ubuntu Live Server only installs a command line interface, with no desktop. To manage your system and its files you will have to know the shell commands.