SSH login possible despite /etc/nologin being present

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Environment

SUSE Linux Enterprise Server 11
SUSE Linux Enterprise Server 11 Service Pack 1
SUSE Linux Enterprise Desktop 11
SUSE Linux Enterprise Desktop 11 Service Pack 1

Situation

SSH users using non-password authentication (such as public key authentication) can still log in despite the file /etc/nologin being present.

Resolution

Edit /etc/pam.d/sshd and change the line

auth requisite pam_nologin.so

to

account requisite pam_nologin.so

Additional Information

The default PAM setup allowing SSH login via public key authentication despite the presence of /etc/nologin avoids accidently locking out remote monitoring scripts or (non-root) administrative staff when just regular users, which in most modern installations log in via a remote X11 server or VNC anyway, aren't supposed to log in.

Disclaimer

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