SSH and SCP

All connections to machines at the Supercomputing Facility are now required to use Secure Shell (ssh). Programs such as telnet, rlogin, rsh, rcp or rexec can compromise both the security of the Facility and the Facility's users by transfering passwords in plain text and by not securely authenticating connections.

If you connect to the TAMU Supercomputing machines from home through the University's modem pool, you will establish your modem connection as usual and then use the ssh client to connect to one of our systems.

You should also get into the habit of using secure copy (scp -- a companion program often bundled with ssh) instead of the traditional ftp utility to transfer files. Scp is more flexible than ftp in that it allows you to transfer directories from one machine to another in addition to just files. There are scp graphical user interfaces for Windows and for Macs.

If you want to run applications with graphical displays from one of our servers and send the display to a Macintosh or a PC running Microsoft Windows, you will need to install an X-Windows emulator.

Installing and Using SSH on your machine

SSH is now quite common and is installed on most machines. If it isn't installed on your machine, you or your system administrator will first have to install an SSH client. Click here for more information on installing SSH clients.

Why SSH

SSH protects you and everyone at the Facility. SSH will encrypt your password, so that malicious people monitoring the network cannot obtain your password. Once inside a system, a malicious person can launch attacks against the system and use it as a platform to launch attacks to other systems.

In addition, for the more technically minded, SSH can protect against (taken from the SSH README):

  • IP spoofing, where a remote host sends out packets which pretend to come from another, trusted host. Ssh even protects against a spoofer on the local network, who can pretend he is your router to the outside.
  • IP source routing, where a host can pretend that an IP packet comes from another, trusted host.
  • DNS spoofing, where an attacker forges name server records.
  • Interception of cleartext passwords and other data by intermediate hosts.
  • Manipulation of data by people in control of intermediate hosts.
  • Attacks based on listening to X authentication data and spoofed connection to the X11 server.