diff -up ./sysctl.conf.5.ori ./sysctl.conf.5

--- ./sysctl.conf.5.ori	2017-04-06 18:59:51.718644400 +0200

+++ ./sysctl.conf.5	2017-04-06 19:00:01.872604143 +0200

@@ -28,6 +28,15 @@ token = value

 Note that blank lines are ignored, and whitespace before and after a token or

 value is ignored, although a value can contain whitespace within.  Lines which

 begin with a # or ; are considered comments and ignored.

+.SH NOTES

+As the

+.BR /etc/sysctl.conf

+file is used to override default kernel parameter values, only a small number of parameters is predefined in the file.

+Use

+.IR /sbin/sysctl\ \-a

+or follow

+.BR sysctl (8)

+to list all possible parameters. The description of individual parameters can be found in the kernel documentation.

 .SH EXAMPLE

 .RS

 .sp