By albertSquid
After following the “How To Set Up Multi-Factor Authentication for SSH” guide (https://www.digitalocean.com/community/tutorials/how-to-set-up-multi-factor-authentication-for-ssh-on-ubuntu-20-04), all users get the Further authentication required / keyboard-interactive message from the server when logging in - also users that doesn’t have multi-factor active.
This messes with the PHP library I use to make SSH connections, phpseclib, as it expects to be prompted for multi-factor, but it actually doesn’t.
Connecting through something like PuTTY, it works just fine; it does note that “Further authentication is required”, but it just ignores it and successfully logs in - I’m just not that lucky with the mentioned library.
I did follow Step 7 in the mentioned guide, but it still seems like it prompts somehow…
Does anyone know how to make the server not send the keyboard-interactive message to the client, when it’s indeed not needed?
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Heya,
If you’re encountering issues with keyboard-interactive authentication while using the phpseclib library, it might be helpful to try configuring the SSH server to avoid prompting for multi-factor authentication if it’s not required for certain users.
You can create a specific Match User block within the /etc/ssh/sshd_config file to specify conditions for the users who will NOT use MFA:
- Match User user1,user2
- AuthenticationMethods publickey
Make sure to replace user1 and user2 with the actual usernames of the non-MFA users. This configuration will require only public key authentication for the specified users, skipping the keyboard-interactive message you mentioned.
After editing the configuration, don’t forget to restart the SSH service:
- sudo systemctl restart ssh
For more details on SSH server configuration, you can refer to this DigitalOcean tutorial.
Hope that this helps!
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