SSH, The Secure Shell: The Definitive Guide, 2nd Edition

Intended Audience

We’ve written this book for system administrators and technically minded users. Some chapters are suitable for a wide audience, while others are thoroughly technical and intended for computer and networking professionals.

End-User Audience

Do you have two or more computer accounts on different machines? SSH lets you connect one to another with a high degree of security. You can remotely log into one account from the other, execute remote commands, and copy files between accounts, all with the confidence that nobody can intercept your username, password, or data in transit.

Do you connect from a personal computer to an Internet service provider (ISP)? In particular, do you connect to a Unix shell account at your ISP? If so, SSH can make this connection significantly more secure. An increasing number of ISPs are running SSH servers for their users. In case your ISP doesn’t, we’ll show you how to run a server yourself.

Do you develop software? Are you creating distributed applications that must communicate over a network securely? Then don’t reinvent the wheel: use SSH to encrypt the connections. It’s a solid technology that may reduce your development time.

Even if you have only a single computer account, as long as it’s connected to a network, SSH can still be useful. For example, if you’ve ever wanted to let other people use your account, such as family members or employees, but didn’t want to give them unlimited use, SSH can provide a carefully controlled, limited-access channel into your account.

Prerequisites

We assume you are familiar with computers and networking as found in any modern business office or home system with an Internet connection. Ideally, you are familiar with network applications like Telnet and FTP. If you are a Unix user, you should be familiar with standard network applications (e.g., ftp) and the basics of writing shell scripts and Perl scripts.

System-Administrator Audience

If you’re a Unix or Macintosh OS X system administrator, you probably know about SSH already. It’s less well known in the Windows world, where secure logins are usually accomplished with radmin (Remote Administrator) and other remote desktop applications, and network file transfers are done using network shares. In contrast, SSH is more focused on the command line and is therefore more scriptable than the usual Windows techniques. SSH also can increase the security of other TCP/IP-based applications on your network by transparently “tunneling” them through SSH-encrypted connections. You will love SSH.

Prerequisites

In addition to the end-user prerequisites in the previous section, you should be familiar with user accounts and groups, networking concepts such as TCP/IP and packets, and basic encryption techniques.