How to Connect

You need an SSH client to connect to Arrow. No other connection protocols are supported. There are 3 general purpose login nodes that you can connect to:

• login1.arrow.tracc.anl.gov
• login2.arrow.tracc.anl.gov
• login3.arrow.tracc.anl.gov

There is also a web-based ThinLinc GUI server available at:

• webaccess4.arrow.tracc.anl.gov

which can be accessed using Chrome, FireFox, or Edge. To use this interface, please contact us for instructions.

When connecting, please pick a random entry from the above list to evenly distribute users over multiple machines. Each login node is a unique server, so if you established an interactive GUI session at some point in the past, you can reconnect to the same login node where you started that GUI session, and you will be able to continue where you left off. This is similar to a remote desktop connection in Windows, and is convenient when connecting from an unreliable network or if you simply prefer to be have a more permanent desktop available. Please not that the login servers have to restarted from time to time, so there is guarantee that a session stays around for weeks or months at a time.

For most remote collaborators, your account starts with "ac.". An example would be "ac.username". These accounts give you access to the ARROW cluster, but to no other resources at Argonne, without exception. If you are an Argonne employee or have an Argonne domain account for other reasons, you will use that account to log in. In this case, don't use the "ANL\" domain prefix as you would on some Windows machines. Just enter the "username" portion.

After entering the password, you will need to confirm your identity using the DUO application. Upon enrollment for a cluster account, you will receive an auto-enrollment Email. Follow the instructions, install the DUO app on your phone, and you are ready to login. As soon as you enter your password in the ssh connection, your phone will prompt you to confirm that you are attempting to log in. After confirming your identity, you will be connected.

Passwords expire on a regular basis (every 6 months or so), and you will need to update your password with Argonne Account Services. You can call 630-252-9999 if you need any help or detailed instructions.

• Access to the TRACC cluster requires the use of an SSH client. Free SSH clients are available for Windows, are included or available for MacOS, and all varieties of Linux or UNIX. SSH clients can be terminal applications to work with command lines (e.g. Putty on Windows), or they can be file transfer utilities (WinSCP, FileZilla, MobaXterm). In any case, cluster connections are all using the SSH protocol (including sftp). Typically you would use a variation of the following command, or provide account and password in your SSH application, such as PuTTy.

ssh [email protected]

• If you are planning to use a single GUI application on the cluster through a plain SSH connection and you are either connecting from a Mac or Linux desktop machine or you have an X server installed on your Windows machine, you may want to enable X11 forwarding to your client using the "-X" option on the command line. Performance is limited, but the mechanism works with limited bandwidth and resources:

ssh -X [email protected]

In some cases, it is necessary to add the "-Y" option, or to replace the "-X" option with "-Y" altogether. It depends on the graphical application you are planning to use.

ssh -X -Y [email protected]

• Alternatively, client software like ThinLinc or X2Go can be used to connect, providing a full graphical user interface and an XFCE desktop. We can provide information on how to download and possibly install the software on your system. We are no longer providing the NoMachine remote desktop software on ARROW.

• Private/Public Key Authentication