Linux

21.7    Changing Kernel Parameters

Many parameters of the kernel can be changed during operation via the /proc file system. The following example shows how you can enable masquerading to use the computer as an internet gateway for other computers:

root# echo 1 > /proc/sys/net/ipv4/ip_forward 

A more elegant way is to use the sysctl command, which is supplied with most current distributions. The analog command to turn off masquerading would look as follows:

root# sysctl -w net.ipv4.ip_forward=0 

sysctl -a returns a list of all kernel parameters along with their current settings. You can use sysctl -p to activate the sysctl settings stored in a file. Usually /etc/sysctl.conf is used as the filename. The syntax is described in the manual page ...