Sunday, January 22, 2012

SSH Mastery: A Very Welcome Addition to Any Unix User's Bookshelf

The first paragraph of this book's afterword reads:

"You now know more about SSH, OpenSSH and Putty than the vast majority of IT professionals! Congratulations".

That claim will be true for any reader of SSH Mastery who has read the book up to that point and has incorporated at least some of the elements of the configurations it describes into their own environments.

"But why a book dedicated to a single command?", you might ask. Almost all Unixes and Unix-likes have incorporated OpenSSH, the free SSH that is developed as part of the OpenBSD project, and OpenSSH comes with excellent documentation in the form of several extensive man pages.

Well, that question in itself justifies this title's existence (there are in fact several programs in the OpenSSH suite), and readers familiar with Michael Lucas' work will appreciate hearing that his latest work is task-oriented and well written, covering anything from the basic secure shell access through to the peculiarities of setting up a virtual private network (VPN) using OpenSSH. An enterprising reader would be able to find all the information in this book or close equivalents using the OpenSSH man pages or other online sources, but this book provides a very concise guide to both the basics and some rather advanced concepts and provides you with the vocabulary and understanding that you will need in order to successfully navigate the man pages.

This book has several highlights, such as the very sensible and useful discussion of key based authentication and how to set things up for a passwordless existence, a number of suggestions on how to distribute and maintain both host keys and user keys as well as very readable and useful introductions to various kinds of tunneling, forwarding and proxying available using the OpenSSH tools.

In particular I enjoyed reading the description of SSH-based virtual private networks (VPNs) in Chapter 13. This is one of the most clearly written and useful treatments I've seen of that subject, and for many readers this chapter alone will be worth the price of the book or even considerably more.

The book very sensibly covers OpenSSH on OpenBSD, FreeBSD and Ubuntu Linux, and users who are compelled to use Microsoft Windows desktops will be pleased to hear that configuration and use information for Putty, the most popular and free SSH client for their environment, is included too everywhere it's relevant to the task at hand.

Before Michael W. Lucas' new title was released in January 2012, the most recent widely available book about the Secure Shell protocol (SSH) and applications that support it was an O'Reilly title dated 2005. So even with high quality documentation available via the manual pages, it was time for a new title on the subject.

This title conveniently grew out of one of Michael W. Lucas' other technical writing projects, the second edition of Absolute OpenBSD. The SSH chapter of that manuscript simply kept growing until it made sense to branch the text off to a separate book. This probably means that the treatment of SSH in the upcoming OpenBSD title will be slimmer again, but separating out the OpenSSH parts as a separate book with information for several different environments added makes sense because it makes high-quality information about important tools available to a larger audience.

I am convinced SSH Mastery is a title that Unix users and system administrators like myself will want to keep within reach on their Kindles or other ebook readers for a quick and convenient refresh of important concepts. If you're a student or learning your Unix skills, you will certainly find this to be a very handy guide that helps you grasp both the basics of SSH and several advanced concepts that are hard to find well described elsewhere.

The ebook is available in several formats via Amazon and other ebook outlets, a printed version is planned but was not yet available at the time of writing (January 22, 2012).

Title: SSH Mastery: OpenSSH, PuTTY, Tunnels and Keys
Author: Michael W. Lucas
Publisher: Tilted Windmill Press (January 18, 2012)