This book is a practical guide to IPv6 addressing Unix and network administrators with experience in TCP/IP(v4) but not necessarily any IPv6 knowledge. Handling IPv6 for the first time is a challenging task even for the experienced system administrator. New concepts and mechanisms make it necessary to rethink well-established methods of the IPv4 protocol. The book focuses on reliable and efficient operation of IPv6 implementations available today rather than on protocol specifications. Consequently, it covers the essential concepts, using instructive and thoroughly tested examples, on how to configure, administrate, and debug IPv6 setups. These foundations are complemented by discussions of best practices and strategic considerations aimed at overall efficiency, reliability, maintainability, and interoperation. The examples in this book cover all relevant aspects concerning Debian GNU/Linux, FreeBSD, and Solaris.