How to Configure Kernel Persistently

To adjust the functioning of the Linux Kernel, there are parameters in kernel that can provide such a mechanism. The followings are some of the example:

1. To list all of the parameters and their values, we can use sysctl command and set kernel parameters:
# sysctl -a

2. To set a parameter, to control IP packet forwarding, default setting is net.ipv4.ip_forward = 0
# sysctl -w net.ipv4.ip_forward = 1
or
# echo 1 > /proc/sys/net/ipv4/ip_forward

3. We need to change the parameter to /etc/sysctl.conf in order to make this setting permanent otherwise after we restart the change will be gone. After we finished setting up, we need to synchronize the new config file with the kernel with the following command:
# sysctl -p