tailieunhanh - Automating UNIX and Linux Administration phần 1

Secure Shell (SSH) giao thức đã cách mạng hóa quản trị hệ thống kể từ khi nó trở nên phổ biến vào cuối những năm 1990. Nó tạo điều kiện thông tin liên lạc, an toàn, mã hóa giữa các máy không tin cậy trên một mạng không an toàn. Toàn bộ chương này là dành cho SSH vì nó đóng một phần quan trọng trong an toàn tự động hoá quản trị hệ thống. | Apress CHAPTER 2 Using SSH to Securely Automate System Administration The Secure Shell SSH protocol has revolutionized system administration ever since it became popular in the late 1990s. It facilitates secure encrypted communication between untrusted hosts over an insecure network. This entire chapter is devoted to SSH because it plays such an important part in securely automating system administration. Since this book is not about installing programs I assume that you already have SSH installed and operating properly. I have based the examples in this book on OpenSSH using version 2 of the SSH protocol. If you are using another version of SSH the principles are the same but the implementation details might be different. For a more thorough and complete discussion of SSH I highly recommend SSH The Secure Shell The Definitive Guide by Daniel J. Barrett and Richard Silverman O Reilly and Associates 2001 . The Basics of Using SSH If you are already familiar with the basic use of SSH you might want to just skim this section. If on the other hand you are an SSH novice you are in for quite a surprise. SSH is very easy and efficient to use and can help with a wide variety of tasks. The commands in this section work fine without any setup assuming you have the SSH daemon running on the remote host . If nothing has been configured all of these commands use password authentication just like Telnet except with SSH the password and all traffic is sent over an encrypted connection. To initiate a connection to any machine as any user and to start an interactive shell use this command ssh user@host This text is excerpted from Chapter 2 of Automating Unix and Linux Administration Apress 2003 ISBN 1-59059-212-3 . 15 Chapter 2 In addition to connecting to remote hosts I often use SSH to log in as root on my local machine because it is quicker then using ssh-agent as discussed later in this chapter. You can also execute any command in lieu of starting an interactive shell.