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How To Login To Acres

SSH

Access to Acres is limited to a few connection points, and is tightly controlled. SSH is the only way to access Acres. From most networks you will need to connect by "jumping" through Polaris.

Before you start, make sure you can log in to Polaris; see this bookstack article. In every method below, you sign in twice: first to Polaris, with your password and a Duo prompt, and then to Acres, with your password only. The first time you connect, you will also be asked to accept a host key for each server.

Windows, Linux, or Mac Terminal

SSH is installed by default in most terminals, including PowerShell and Command Prompt on Windows 10 and 11.

Connecting directly

If you are on a network that can reach Acres directly, connect with:

ssh username@acres.clarkson.edu

Connecting through Polaris (ProxyJump)

On more restricted networks, including off campus, use the -J option to jump through Polaris in one command:

ssh -J username@polaris.clarkson.edu username@acres.clarkson.edu

Replace username with your Clarkson username.

Making it permanent (recommended)

To avoid typing the jump every time, add this to your SSH config file. It is ~/.ssh/config on Linux and Mac, and C:\Users\<you>\.ssh\config on Windows. Create the file if it does not exist.

Host polaris
    HostName polaris.clarkson.edu
    User username

Host acres
    HostName acres.clarkson.edu
    User username
    ProxyJump polaris

After that, ssh acres is all you need. The same setting also works for scp, sftp, and editors that connect over SSH, such as VS Code's Remote-SSH extension. For example:

scp myfile.txt acres:~/

PuTTY

These steps need PuTTY 0.77 or newer. Check the version under Help → About PuTTY, and update from the PuTTY website if it is older.

  1. Open PuTTY. In the Session category, enter:
    • Host Name: acres.clarkson.edu
    • Port: 22
    • Connection type: SSH
  2. Go to Connection → Data and set Auto-login username to your Clarkson username.
  3. Go to Connection → Proxy and enter:
    • Proxy type: SSH to proxy and use port forwarding
    • Proxy hostname: polaris.clarkson.edu
    • Port: 22
    • Username: your Clarkson username
    • Leave Password blank. PuTTY will ask for it when you connect, followed by the Duo prompt.
  4. Go back to Session, type a name such as Acres under Saved Sessions, and click Save.
  5. Click Open. Sign in to Polaris first, then to Acres.

Next time, select Acres from Saved Sessions and click Open.

WinSCP

  1. Open WinSCP. In the Login window, click New Site and enter:
    • File protocol: SFTP
    • Host name: acres.clarkson.edu
    • Port number: 22
    • User name: your Clarkson username
    • Leave Password blank.
  2. Click Advanced..., then go to Connection → Tunnel.
  3. Check Connect through SSH tunnel and enter:
    • Host name: polaris.clarkson.edu
    • Port number: 22
    • User name: your Clarkson username
    • Leave Password blank.
    • Leave Local tunnel port on Autoselect.
  4. Click OK, then Save, and give the site a name such as Acres.
  5. Click Login. WinSCP asks for your Polaris password and Duo prompt first, then your Acres password.

Things to know

  • For security, Polaris only forwards connections to SSH on Acres (acres.clarkson.edu, port 22). Port forwarding through Polaris to any other machine or port is blocked, as are tunnels to Polaris itself.
  • Always use the full name acres.clarkson.edu when setting up a connection.
  • If you only need a quick session, you can still SSH to Polaris first and then run ssh acres.clarkson.edu from there.
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