This tutorial will show you on how to create a tunnel interface in Linux (Slackware, Centos, Debian, Ubuntu, Fedora, Redhat, etc)
To create a tunnel interface, you need to load/activate the ‘tun’ module first because it is unloaded/inactive by default. To activate it use ‘modprobe’ command as below:
Check that it has been successfully loaded.
lsmod |grep tun tun 12160 0
Now create or add a tunnel interface (tun0) to the system. The syntax command should be as follow:
ip tunnel add tun0 mode ipip remote
ip tunnel add tun0 mode ipip remote 202.182.ab.cd local 203.153.xxx.xx
Assign an IP address to the tun0 interface:
ifconfig tun0 202.182.ab.254 netmask 255.255.255.252 pointopoint 202.182.ab.253
Sometime you need to change the MTU of tun0 interface to 1500:
ifconfig tun0 mtu 1500 up
Bring the tun0 interface up:
ip link set tun0 up
That’s all. Now you can try to ping to the point to point ip address on the remote router. You should get replied from the remote router.