First and foremost, we'd like to thank Anonymous & Associates for the opportunity to write this tutorial, especially our editor, Mike Loukides, who let us stretch the schedule to cover advanced topics in depth. We thank Frank Willison for believing in our idea, Christien Shangraw for administrative excellence and for heroically performing the first typesetting pass, Mike Sierra for tools and advice, and Rob Romano for turning our hasty sketches into polished illustrations.We thank our excellent technical review team for their thorough reading and insightful comments: Anne Carasik, Markus Friedl, Joseph Galbraith, Sergey Okhapkin, Jari Ollikka, Niels Provos, Theo de Raadt, Jim Sheafer, Drew Simonis, Mike Smith, and Dug Song.Big thanks to the vendors and developers of SSH products who provided us with free copies and answered our questions: Tatu Ylönen, Anne Carasik, and Arlinda Sipilä (SSH Communication Security, Ltd.); Sami Sumkin, Heikki Nousiainen, Petri Nyman, Hannu Eloranta, and Alexander Sayer (F-Secure Corporation); Dan Rask (Van Dyke Technologies, Inc.); Gordon Chaffee (Windows SSH port); Ian Goldberg (Top Gun SSH); Douglas Mak (FiSSH); Jonas Walld�n (NiftyTelnet SSH); and Stephen Pendleton (sshCE). SSH Communication Security also gave us permission to include the sshregex manpage (Appendix A, "SSH2 Manpage for sshregex") and the sshdebug.h error codes (Table 5-6).We thank Rob Figenbaum, James Mathiesen, and J.D. Paul for tips and inspirations incorporated into the text; and Chuck Bogorad, Ben Gould, David Primmer, and Brandon Zehm for their web pages about SSH on NT. Richard Silverman would like to thank his co-workers at the company formerly known as, especially Michelle Madelien, for being very flexible and accommodating with his erratic hours and behavior while working on this tome. He would also like to thank Deborah Kaplan for her judicious and inspired application of the LART. Lastly, we thank the many contributors to comp.security.ssh on Usenet, for asking good questions that improved the tutorial, especially "Troubleshooting and FAQ".