OS X: Connecting with SSH

Because of the sensitive nature of information being transmitted, ECN users should attempt to use secure communication methods whenever possible. Non-secure services at Purdue are being disabled in favor of secure services like SSL and SSH. SSH is built into Mac OS X, and is highly configurable. SSH should always be used when connecting to an ECN server.

All versions of OS X have SSH built in. However, always make sure your computer is up to date by selecting Software Update... from the Apple menu. Occasionally, updates to the SSH protocol and other secure communication protocols are released by Apple.

You can access the SSH command line utility through Terminal.app (found in /Applications/Utilities/Terminal.app). To connect to an ECN server, you will append the command "ssh" with information about yourself and the server you're connecting to. The command should appear as follows:

ssh -2 -l username server

The 2 flag forces SSH to connect using SSHv2, a more secure form of SSH. The l (that's a lowercase "L", not the number "1") flag instructs SSH to use the username following the flag instead of the user executing the SSH command. This can be helpful in ECN labs. Replace username with your ECN user name, and server with the ECN server you wish to connect to. Here's an example of user jsmith connecting to dynamo:

ssh -2 -l jsmith dynamo.ecn.purdue.edu

There's a simpler way to connect via SSH if you're not concerned about using the SSHv2 flag. Format your command as such:

ssh jsmith@dynamo.ecn.purdue.edu