system_cmds-643.1.1.tar.gz

[apple/system_cmds.git] / nologin.tproj / nologin.5

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.\"     @(#)nologin.8	8.1 (Berkeley) 6/19/93
.\" $FreeBSD: src/usr.sbin/nologin/nologin.5,v 1.15 2007/05/10 11:22:24 yar Exp $
.\"
.Dd May 10, 2007
.Dt NOLOGIN 5
.Os
.Sh NAME
.Nm nologin
.Nd disallow logins
.Sh DESCRIPTION
Programs such as
.Xr login 1
disallow logins if the
.Nm
file exists.
The programs display the contents of
.Nm
to the user if possible and interrupt the login sequence.
This makes it simple to temporarily prevent incoming logins systemwide.
.Pp
To disable logins on a per-account basis,
investigate
.Xr nologin 8 .
.Sh SECURITY
The
.Nm
file is ignored for user root by default.
.Sh IMPLEMENTATION NOTES
The
.Nm
feature is implemented through
.Xr login.conf 5 ,
which allows to change the pathname of the
file and to extend the list of users
exempt from temporary login restriction.
.Pp
PAM-aware programs can be selectively configured to respect
.Nm
using the
.Xr pam_nologin 8
module via
.Xr pam.conf 5 .
.Pp
The
.Nm
file will be removed at system boot if it resides in
.Pa /var/run
and
.Va cleanvar_enable
is set to
.Dq Li YES
in
.Xr rc.conf 5 ,
which is default.
Therefore system reboot can effectively re-enable logins.
.Sh FILES
.Bl -tag -width ".Pa /var/run/nologin" -compact
.It Pa /var/run/nologin
default location of
.Nm
.El
.Sh SEE ALSO
.Xr login 1 ,
.Xr login.conf 5 ,
.Xr pam.conf 5 ,
.Xr rc.conf 5 ,
.Xr nologin 8 ,
.Xr pam_nologin 8 ,
.Xr shutdown 8