SSH

SSH is a collection of programs that allow you to securely access remote (non-local) computers on a network. It provides secure replacements for many standard protocols for remote access such as telnet, ftp, etc.

The list of programs that SSH provides includes:

• ssh - secure shell. A replacement for telnet
• sftp - secure file transfer. A replacement for ftp(file transfer protocol)
• scp - secure copying of files. Allows you to copy files between local and remote computers, and between two different remote computers, securely. Extension of the Linux cp command

In addition to providing these services ssh can be used to tunnel any protocol, such as POP3 or IMAP, securely over a network. For example, you may want to securely access your email using IMAP. By tunneling it over ssh you will be able to access it securely without making any any changes in your existing setup.

The SSH suite replaces existing utilities so well that you should stop using the existing utilities. Even though you may be told, or your instructor might say, to use telnet, use ssh instead. Even though you may be told to use ftp, use sftp instead.

Availability of ssh

The availability of ssh depends on the operating system that you are using:

• Linux/UNIX - Almost all Linux/UNIX systems have ssh installed as part of the standard distribution. If not, it is relatively easy to have installed.
• MS Windows - Is not included in MS Windows. Must be installed. We have written complete MS Windows ssh installation instructions. Note that to get all of ssh capabilities you would need to install a shell version of it and use it in a MS Windows shell, or use it in Cygwin.

The lab computers in this department that run MS Windows have a ssh and sftp installed already.

Using SSH on MS Windows

To be completed.

Using SSH on Linux/UNIX

Students can access loki over a network using the full Internet name: loki.cs.kent.edu. They would typically ssh into loki with X-Window tunneling enabled. The command to do this is:

ssh -X username@loki.cs.kent.edu

Where username is your username on loki. The -X flag provides for X-Window tunneling.

You then have secure shell access to loki. In addition, any X-Window programs that you start in loki shell will be display, securely of course, on your local X-Windows server (the X-Windows that is running on your local computer).

ssh is very configurable and the above command can be easily shortened by configuration to:

ssh loki

To do this put the following in your ssh configuration file:

loki:
Host            loki.cs.kent.edu
User            username
ForwardX11      yes

Check your documentation, using man or info on ssh, to see where this is.