duo/two-factor authentication (2fa)

Beginning in September 2023, we are requiring duo/2fa for ssh connections to the CS computers from off-campus networks.

Duo will not be required if you are sshing to CS from a computer on the campus network (e.g., your laptop on the eduroam wireless).

Duo will also not be required if you are using ssh public key authentication (see help page below).

If you ssh to the CS computers from an off-campus computer, you will either see a menu like this:

$ ssh csmajor1@cslab.cs.swarthmore.edu
Duo two-factor login for csmajor1

Enter a passcode or select one of the following options:

 1. Duo Push to XXX-XXX-5555
 2. Duo Push to iPad (iOS)
 3. Phone call to XXX-XXX-5555

Passcode or option (1-5): 1
Success. Logging you in...

or you will just get an automatic push notification on your phone. Once you accept the duo notification, your ssh login should proceed like usual.

duo miniFAQ

Q: Do I need to set up duo for CS?

A: No. You should have already set up duo for use with other college services (see the ITS duo help page)

Q: Will I need to bring my phone to class or lab?

A: No. Duo will only be used for ssh logins from off-campus computers (e.g., when you are at home on break, and ssh to the CS lab computers). Duo will not be used when you log in sitting at a classroom computer.

Q: Will I have to use duo when I ssh to CS from my laptop?

A: If your laptop is on the campus network, the campus wireless (eduroam), or is using the campus VPN, then no. Otherwise, yes (but see next question about ssh keys).

Q: Duo is annoying. How can I avoid having to use duo?

A: Set up ssh keys for your CS account and use ssh public key authentication.

Q: What about atom ftp-remote-edit, or vscode, or sshfs? Will those require duo?

A: As long as the application prompts for a password, duo should push a notification and, once you accept, everything should work. For example, with atom’s ftp-remote-edit, one of the EditServer options is LogonType, and if you choose “Username/Prompt for password”, it should work fine with duo.

Also, if you set up ssh keys for your CS account and use ssh public key authentication, that should allow you to avoid needing duo for these apps.

See also:

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