VETH is a daemon that virtualizes a ethernet card in Linux. The virtualization is done via Universal TUN/TAP Driver. Linux has an implementation that does the work, but partially. Sometimes, this emulation doesn't work as expected. Because of this, I wrote VETH, to help in this situations.
For example, if you want to have more than one IP address obtained via DHCP probably you know that's impossible. With VETH you can attach a virtual ethernet into an existent NIC card, and the run dhclient in it to obtain a new IP.
modprobe tun, you need to create the device
file: mknod /dev/tun c 10 220 as root. If you
uses devfs this isn't needed.
The documentation is in the package. Well, isn't as big as you want it, but... it helps! ;-)