VETH 1.0 review

VETH is a daemon that creates a virtual ethernet card in Linux

License: GPL (GNU General Public License) File size: 14K Developer: Nestor Pe?a

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VETH is a daemon that creates a virtual ethernet card in Linux. This is done via the Universal TUN/ TAP Driver. It is useful to request more than one IP address via DHCP with a virtual ethernet card attached to an existing NIC.

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 be helpful 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.

Perhaps you are saying "hey, man, don't mess with me, I can do that with aliasing. With an ifconfig eth0:1 I have a new ethernet". OK, perhaps, perhaps...

It isn't 100% true. Look at this scenario:

You have a DSL modem working as a bridge. You have a firewall with exactly 2 NICs, no more. One of these NICs is crossover-connected to your modem, and another is in your internal subnet.

Requirements:
A linux 2.4 kernel. I don't know if the ioctl() calls changed in 2.6, but you can test it.
The tun module loaded in the system. This module is called «Universal TUN/TAP driver». Probably after doing a 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.