Michael W. Lucas published his new book “SSH Mastery” (no link to an online store, get it from your preferred online or offline one in your part of the world).
Do you think you know a lot about SSH? I thought I did when Michael searched technical proof-readers for this book. I offered to have a look at his work in progress and he gently accepted (while I do not get money for this, I am one of the persons he thanks for the technical review in the beginning, so I am involved somehow and as such you should take the following with a grain of salt).
I already had user restrictions in place before the review, but now I narrowed down some restrictions based upon some conditionals. I already used SSH tunnels for various things before (where legally applicable), but I learned some additional VPN techniques with SSH. I already used multiple ssh-keys for various things, but Michael provides some interesting ways of handling a large-volume of ssh-keys over multiple machines. … I really hope that my review was as valuable for Michael, as it was for me to do the review.
He ends the book with “You now know more about SSH, OpenSSH and Putty than the vast majority of IT professionals! Congratulations”, and this is true, and all that in his writing style where you can come with a problem, read about it, and leave with a solution (normally with a little bit of entertainment in between).
I know a lot of people which work daily with SSH, and they know only a small part of what is presented in this book. In my opinion this book is a must-have for every System/Database/Application/Whatever Administrator in charge of something on an UNIX-like system, and even “normal users” of SSH (no matter if they use PuTTY, or a ssh command line program on an UNIX-like system (most probably it will be OpenSSH or a clone of it)) will get some helpful information from this book.
I can only recommend it.