1.\" Copyright (c) 1999 Chris Costello <chris@FreeBSD.org> 2.\" All rights reserved. 3.\" 4.\" Redistribution and use in source and binary forms, with or without 5.\" modification, are permitted provided that the following conditions 6.\" are met: 7.\" 1. Redistributions of source code must retain the above copyright 8.\" notice, this list of conditions and the following disclaimer. 9.\" 2. Redistributions in binary form must reproduce the above copyright 10.\" notice, this list of conditions and the following disclaimer in the 11.\" documentation and/or other materials provided with the distribution. 12.\" 13.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 14.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 15.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 16.\" ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 17.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 18.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 19.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 20.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 21.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 22.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 23.\" SUCH DAMAGE. 24.\" 25.Dd June 30, 2022 26.Dt SYSCTL.CONF 5 27.Os 28.Sh NAME 29.Nm sysctl.conf 30.Nd kernel state defaults 31.Sh DESCRIPTION 32The 33.Pa /etc/sysctl.conf 34file is read in when the system goes into multi-user mode to set default 35settings for the kernel. 36The 37.Pa /etc/sysctl.conf 38file is in the format of the 39.Xr sysctl 8 40command, i.e., 41.Bd -literal -offset indent 42sysctl_mib=value 43.Ed 44.Pp 45Comments are denoted by a 46.Dq # 47at the beginning of a line. 48Comments can also exist at the end of a line, 49as seen in the 50.Sx EXAMPLES 51section, below. 52.Pp 53For kernel modules loaded via 54.Xr rc.subr 8 55system, 56additional module-specific settings can be applied 57by adding a file in the same format named 58.Pf /etc/sysctl.kld.d/<module name>.conf . 59.Sh FILES 60.Bl -tag -width /etc/rc.d/sysctl_lastload -compact 61.It Pa /etc/rc.d/sysctl 62.Xr rc 8 63script which processes 64.Nm 65early on in the process of transitioning to multi-user mode. 66.It Pa /etc/rc.d/sysctl_lastload 67.Xr rc 8 68script which processes 69.Nm 70shortly before the system reaches the multi-user mode. 71.It Pa /etc/sysctl.conf 72Initial settings for 73.Xr sysctl 8 . 74.It Pa /etc/sysctl.conf.local 75Machine-specific settings for sites with a common 76.Pa /etc/sysctl.conf . 77.It Pa /etc/sysctl.kld.d 78Module specific settings for kernel modules loaded via 79.Xr rc.subr 8 . 80.El 81.Sh EXAMPLES 82To turn off logging of programs that exit due to fatal signals you may use 83a configuration like 84.Bd -literal -offset indent 85# Configure logging. 86kern.logsigexit=0 # Do not log fatal signal exits (e.g., sig 11) 87.Ed 88.Sh SEE ALSO 89.Xr rc.conf 5 , 90.Xr rc 8 , 91.Xr sysctl 8 92.Sh HISTORY 93The 94.Nm 95file appeared in 96.Fx 4.0 . 97.Sh BUGS 98If loadable kernel modules are used to introduce additional kernel 99functionality and sysctls to manage that functionality, 100.Nm 101may be processed too early in the boot process to set those sysctls. 102Please consult 103.Xr rcorder 8 104to learn more about the ordering of 105.Xr rc 8 106scripts. 107