Display the status of ip_forward:
cat /proc/sys/net/ipv4/ip_forward
0 (Disable)
or
sysctl -p
Enable the ip_forward :
sysctl -w net.ipv4.ip_forward=1
or
echo 1 > /proc/sys/net/ipv4/ip_forward
or
Permanent setting using /etc/sysctl.conf
vim /etc/sysctl.conf
net.ipv4.ip_forward = 1
Load the kernel parameter using -p
sysctl –p
or
sysctl -p /etc/sysctl.conf
Enjoy :)