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Use the TAP adapter as a virtual network interface driver

Posted: Wed Jun 01, 2011 12:59 pm
by Nimral
Hi folks,

is it possible to configure the openVPN TAP-Win32 adapter driver so it does effectively mimic a second network interface, bridged to the LAN interface the machine has? No VPN involved at all?

Background: I have a laptop computer with 1 built-in network interface, but need to run two entirely different IP configurations concurrently. Right now I use a second USB Ethernet NIC, and everything is fine, except I have another USB dongle hanging from my machine, and 2 ethernet cables running to the nearest switch.

I searched the net up and down for a TAP driver, which gives me what I want on Windows 7 (64 Bit), but with no luck so far.

Any useful informations welcome ...

Thx

Armin.

Re: Use the TAP adapter as a virtual network interface drive

Posted: Wed Jun 01, 2011 1:08 pm
by janjust
yes , you can bring up a tap-win32 adapter without using a VPN; don't use DHCP, assign a static IP and make sure the status is 'always connected'. Of course, all packets sent to this interface disappear to the "Land where Bits are Eternally Happy" .

Re: Use the TAP adapter as a virtual network interface drive

Posted: Wed Jun 01, 2011 1:30 pm
by Nimral
Hi Janjust,

thanks for your reply ... but I don't want my Bits "ethernally happy", at least not before they made a remote ethernet interface happy :-)

Instead I wand the driver send and receive packets like a physical interface, borrowing the MAC layer from the real physical interface. Maybe I was not clear when I said "bridged to the LAN interface", but a better term didn't come to my mind yet ...

Armin.

Re: Use the TAP adapter as a virtual network interface drive

Posted: Wed Jun 01, 2011 3:10 pm
by janjust
if you bridge two adapters both get the same IP; what you really want is an IP alias for your ethernet adapter, which I am not sure windows supports....

Re: Use the TAP adapter as a virtual network interface drive

Posted: Thu Jun 02, 2011 2:30 pm
by Nimral
janjust wrote:if you bridge two adapters both get the same IP; what you really want is an IP alias for your ethernet adapter, which I am not sure windows supports....
Sorry, don't agree. But re-reading my post I still wasn't entirely clear.

What I am looking for is a network adapter, completely in software, which uses the physical network adapter to communicate. To do this, of course, the software driver would need to assign itself a MAC address different from the existing LAN adapter. Seen from the outside, the computer would actually seem to have two NICs, seen from the operating system level it would also have 2 different NICs, but in reality only one physical network adapter would be present.

Such NIC emulation software is possible, and was around for XP (virtnet driver), but I found none for WIndows 7 so far.

Armin

Btw, Windows supports additional ("helper") IP adresses on one interface, but this is not what I need.