Virtual Networks
# TUN/TAP
Kernel network drivers used for tunneling
TUN and TAP can’t be used together because they transmit and receive packets at different layers of the network stack.
- TUN, namely network TUNnel, simulates a network layer device and operates in layer 3 carrying IP packets.
- TAP, namely network TAP, simulates a link layer device and operates in layer 2 carrying Ethernet frames. TAP can be used to create a user space network bridge Packets sent by an operating system via a TUN/TAP device are delivered to a user space program which attaches itself to the device. A user space program may also pass packets into a TUN/TAP device. In this case the TUN/TAP device delivers (or “injects”) these packets to the operating-system network stack thus emulating their reception from an external source.