Pro OpenSSH (Pro) by Michael Stahnke

SSH, or Secure Shell, is the de facto standard among users and administrators who wish to establish secure communication between disparate networks. This book is authored by a Fortune 100 system administrator, who will provide you with a highly practical reference for configuring and deploying OpenSSH in your own environment.
Some of the topics covered in this book include: OpenSSH installation and configuration, key management, secure logging, client/server architectures, and digital certificates. The author also provides you with complete deployment scenarios that arise daily in enterprise environments, both large and small.