Connect internet when using OpenVPN - Ubuntu 16.04

1. Setup OpenVPN using network manager

2. Open termainal, type

default_gateway=$(/sbin/ip route | awk '/default/ { print $3 }')
arr=(`echo ${default_gateway}`);
#echo "${arr[1]}"
sudo route add default gw "${arr[1]}"  wlp62s0
sudo route add -net 10.0.0.0 netmask 255.255.255.0 dev tun0

wlp620: main card connect internet (wifi or cable)
tun0: virtual interface of VPN connection
10.0.0.0 : base ip of VPN connection (ex: 10.0.0.3)


3. Save as changegateway
4. chmod +x changegateway
5. ./changegateway