JLab SSH Documentation Home

JLab SSH Documentation

What is SSH?

SSH is a secure remote login and file copy utility. You use SSH to log in to remote hosts, it will automatically encrypt your entire session and protect it from eavesdroppers. This helps prevent your password from being stolen and your account from being compromised. SSH can also encrypt your X Window session, allowing you to securely run GUI programs on remote computers.

Who should use SSH?

Everybody, on site, or not. Unfortunately, not all parts of the world currently have access to the SSH software. If you do, you should definitely use it anytime you log into any networked machine, whether it is on site or not. This includes file transfers, too. The bottom line is: do not use telnet, rlogin, rsh or ftp. There are several benefits to using ssh:

Automatic authentication of users, no passwords sent in clear text to prevent the stealing of passwords
Multiple strong authentication methods that prevent such security threats as spoofing identity
Encryption and compression of data for security and speed (such as X traffic)
Secure file transfer
Tunneling and encryption of arbitrary connections. This feature allows you to display many X windows applications running on remote hosts on your local display.

SSH can authenticate your username (i.e. login you in) in two different ways.

Password authentication: Using this mode, ssh is almost identical to the programs telnet or rsh. When you make a connection, you are asked for your password. You type it in and you are either logged in or denied. You password is first encrypted and then sent over the network and then decrypted at the remote host. This is the mode that most users will be encouraged to use, as it requires no additional setup or configuration.
DSA Authentication: With this mode, you develop a public/private key pair. You then place your public key on a remote host that you wish to connect to. This is very similar to using the .rhosts file to make connections via rlogin. You may also chose to use a passphrase with your public key. This will make the connection require that the passphrase be typed in before the connection is established. But this is optional, therefore you could chose to not have a passphrase and then the connections will proceed immediately, just as rlogins do.

What documentation is available for SSH?

All Platforms

SSH Upgrade FAQ

See how our convesion to SSH version 2 clients will affect you.

Unix

SSH Introduction	A good introduction to SSH which explains many of its features and gives examples of how to use them. Start here if you're new to SSH.
How to use the SSH agent for Linux	You can configure SSH to log you in to a remote system without asking for a password. This document shows you how.
SSHv2 Training	PowerPoint/OpenOffice.org Presentation on using SSH, including configuring keys and taking advantage of the SSH Agent

Windows

PuTTY Installation and Configuration

Documentation on our new preferred Windows SSH client, PuTTY.

This document is maintained by {helpdesk@jlab.org}