How to Connect

You need an SSH client to connect to Arrow. No other connection protocols are supported. There are 4 general purpose login nodes that you can connect to:

• login1.arrow.tracc.anl.gov
• login2.arrow.tracc.anl.gov
• login3.arrow.tracc.anl.gov
• login4.arrow.tracc.anl.gov

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.

How to Connect: Details

SSH

• Access to the TRACC cluster requires 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). In any case, cluster connections are all using the SSH protocol (including sftp).

• If you're using a simple graphical application on the cluster through an 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. This is a method that uses strictly the old X protocol, and performance is very limited (due to the SSH encryption overhead). You should consider using one of the remote GUI options listed below instead if you can. If you want to keep it simple though, you can do this (using typically a corresponding check box in Windows clients):

ssh -X [email protected]

--Amiot (talk) 15:28, January 14, 2025 (CST)

• Alternatively, client software like the NoMachine NX client can be used to connect, providing a full graphical user interface. This requires the installation of the free NoMachine client software.

• Another alternative is the free X2Go client, which provides a near identical user experience. Details can be found here.

Access restricted to authorized hosts

• Access to the cluster is currently restricted to pre-approved hosts. Please contact us clicking to send email with the hostnames of the systems from which you would like to access the cluster. Argonne users with Argonne Domain accounts can connect through Argonne's VPN service; please contact us by clicking to send email for details.

• Under Windows, you can find out your host name with the command "ipconfig". Note that IP addresses beginning with "10." or "192.168." are private addresses assigned by your home router, and those are not accessible from outside your home network. If you have such an address, you can usually find your public IP address at (for example) http://whatismyip.com.