configure_ssh_2fa only enabled the deprecated ChallengeResponseAuthentication
directive (removed as a usable knob in modern OpenSSH; it no longer controls
keyboard-interactive). The base tsys-sshd-config ships
KbdInteractiveAuthentication no, so on Debian 13 (OpenSSH 9.x/10.x)
keyboard-interactive stayed disabled. With AuthenticationMethods set to
"publickey,keyboard-interactive", sshd -t then failed:
Disabled method "keyboard-interactive" in AuthenticationMethods list ...
AuthenticationMethods cannot be satisfied by enabled authentication methods
which aborted provisioning under errexit.
Add the modern KbdInteractiveAuthentication yes directive alongside the
legacy one so 2FA works on both current and older OpenSSH.
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mrcharles
40dfda47f2