Secure Shell (SSH) Access
In order to increase the security of networks, servers now support Secure Shell (SSH) connections. SSH is a secure shell system; it encrypts data between a client and server. This is in contrast to telnet (or FTP, or most other services), that send information in plain text. SSH encrypts all traffic, including passwords, typed text, X graphics, etc. It is meant to be a drop-in replacement for both telnet and rsh.
Some servers have been upgraded to SSH2. If you experience problems connecting via SSH, try modifying your session settings to connect via the SSH2 protocol with 3DES encryption.
In order to connect via SSH, you will have to install an SSH client on your computer. The standard Windows telnet client, and most of the older third-party telnet clients do not offer SSH capability. We recommend the following SSH clients:
Other clients for Windows, Mac, and other operating systems are listed at http://www.openssh.com.
What is SSH?
SSH was one of the first tools built by the architects of the Internet so that resources could be shared easily.
SSH is the means to connect directly to your web server. What this means is that you, from your computer at home or work, can log-on to your hosting server and utilize the software programs or data files located there. An easy way to visualize this is to think of your keyboard directly attached to a distant computer and not to your local computer.
What can I do in SSH?
Similar in appearance to the Windows DOS prompt, you can type in commands (yes, TYPE in commands – no clicking allowed here) to perform specific functions. The most commonly used commands are simple and easy to remember. There are several functions that you may wish to perform in telnet, such as untarring (unzipping) files, moving entire directories from one location to another, deleting files or entire directories, etc.
Here are some programs that are available to you in SSH:
- pine – a more powerful email program
- ftp – to FTP onto other sites
- ssh – to telnet to other sites
- pico – an easy to use text editor
In general, Telnet provides a pretty complete POSIX environment. You access these programs by typing in their names and then following commands relevant to each program. If you need help with any of the programs, at the shell prompt, type man and the name of the program (e.g., man pine to get instructions for that program online. If your problem is not knowing the name of the program, try apropos {subject} (e.g., apropos mail).
SSH is CaSe SeNsItIvE!
It is important to remember that Unix is case-sensitive, and that “Index.htm” is not the same as “index.htm.” This also holds true for your account passwords.
Do I HAVE to use SSH?
Most of the functions you can perform in telnet, you can perform using other tools as well. For example, you can edit your maillists, redirect file, and permissions either in telnet or from your control panel. It’s your choice — just use what you’re comfortable with.
Some Basic UNIX Commands
The following are some basic commands that will help you become acquainted with the UNIX environment:
- ls: Lists the contents of your directory.
- ls -a: Lists all files in the directory, including hidden files (hidden files begin with a “.” (e.g., .htaccess.)
- cd: Changes the directory. For example, to move from your “root” or “home” directory to your “www” directory, type the command, cd www; to move up one level (e.g., from your “www” directory back to your “root” directory), type cd …
- cp: Copy a file. Syntax is cp <sourcefile> <destinationfile>.
- mv: Move a file, or rename a file. Syntax is mv <source> <target>.
- rm: Remove, or delete, a file. Syntax is rm <filename>.
NOTE: Use this command carefully — there is no UNDO command in UNIX. - mkdir: Creates a directory. Usage is mkdir <directoryname>.
- rmdir: Remove or delete a directory. Syntax: rmdir <directoryname>.
- pwd: Returns the system path to the current working directory. Useful not only when you’re lost, but when you need the correct system path for CGI files, etc.
