pam_nologin 8 Linux-PAM Manual pam_nologin Prevent non-root users from login pam_nologin.so file=/path/nologin successok pam_nologin is a PAM module that prevents users from logging into the system when /etc/nologin exists. The contents of the /etc/nologin file are displayed to the user. The pam_nologin module has no effect on the root user's ability to log in. file=/path/nologin Use this file instead the default /etc/nologin. successok Return PAM_SUCCESS if no file exists, the default is PAM_IGNORE. The auth and acct module types are provided. PAM_AUTH_ERR The user is not root and /etc/nologin exists, so the user is not permitted to log in. PAM_BUF_ERR Memory buffer error. PAM_IGNORE This is the default return value. PAM_SUCCESS Success: either the user is root or the /etc/nologin file does not exist. PAM_USER_UNKNOWN User not known to the underlying authentication module. The suggested usage for /etc/pam.d/login is: auth required pam_nologin.so In order to make this module effective, all login methods should be secured by it. It should be used as a required method listed before any sufficient methods in order to get standard Unix nologin semantics. Note, the use of successok module argument causes the module to return PAM_SUCCESS and as such would break such a configuration - failing sufficient modules would lead to a successful login because the nologin module succeeded. nologin5 , pam.conf5 , pam.d5 , pam8 pam_nologin was written by Michael K. Johnson <johnsonm@redhat.com>.