How can I create a virtual tap interface via command line

Hello,

I am currently using Tomato by Shibby AIO 130. I will need help to create a virtual tap interface via command line.

In the tomato GUI, if I go to "VPN Tunneling" -> "OpenVPN Server", choose "TAP" for Interface Type in the "Basic" tab, then click on the "Start Now" button. I can create the virtual tap interface "tap21". See the attached screenshot. I don't need to use OpenVPN but I do need the tap interface. However, this virtual tap interface will be gone after router reboot. That...

How can I create a virtual tap interface via command line