checking status

$ sysctl net.ipv4.ip_forward
net.ipv4.ip_forward = 0
	

or just checking out the value in the /proc system

$ cat /proc/sys/net/ipv4/ip_forward
0
	

enable

sysctl -w net.ipv4.ip_forward=1
	

or

	
#redhat
echo 1 > /proc/sys/net/ipv4/ip_forward
#debian/ubuntu
echo 1 | sudo tee /proc/sys/net/ipv4/ip_forward;
	
	

disable

sysctl -w net.ipv4.ip_forward=0
	

or

	
echo 0 > /proc/sys/net/ipv4/ip_forward
	
	

without rebooting the system

		
$ sysctl net.ipv4.ip_forward
net.ipv4.ip_forward = 0
		
		

# Disable ping requests
net.ipv4.icmp_echo_ignore_all = 1