This book is organized by concept rather than syntax. We begin with an overview and progressively lead you deeper into the functionality of SSH. So, we might introduce a topic in Chapter 1, show its basic use in Chapter 2, and reveal advanced uses in Chapter 7. If you prefer the whole story at once, Appendix E presents all commands and configuration options in one location.
We focus strongly on three levels of server configuration, which we call compile-time, serverwide, and per-account configuration. Compile-time configuration (Chapter 4) means selecting appropriate options when you build the SSH clients and servers. Serverwide configuration (Chapter 5) applies when the SSH server is run and is generally done by system administrators, while per-account configuration (Chapter 8) can be done anytime by end users. It’s vitally important for system administrators to understand the relationships and differences among these three levels. Otherwise, SSH may seem like a morass of random behaviors.
Although the bulk of material focuses on Unix implementations of SSH, you don’t have to be a Unix user to understand it. Fans of Windows and the Macintosh may stick to the later chapters devoted to their platforms, but a lot of the meaty details are in the Unix chapters, so we recommend reading them, at least for reference.
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