passing data transparently

Hi all,
I am helping a friend with this setup. They have a device which has a fixed ip (say 1.2.3.4) which talks with its software running on MS-Windows which must be physically connected to it and must have a specific IP (say 1.2.3.5) only. Now it happens that the laptop running that software is in a branch office so physical connection is not possible. So, we have thought of,

Device(1.2.3.4)<-->(1.2.3.5)Linux(ext add.)<-->INTERNET<-->(ext. add.)Linux2(1.2.3.4)<-->(1.2.3.5)MS-Win Laptop

The idea is that the laptop thinks it is dealing with device and the device thinks that it is dealing with laptop, while both of them are dealing with a black box (Linux) which is transparently passing the data.

Is this model right or can we make it better? I am unable to figure out the exact routing (and iptables) part. Can someone help in this? Do we need ip or route will be sufficent? Or is there any software which will pass data transparently like nc or xinetd does for a specific port?

Thanks in advance.
With warm regards,
Payal

Am 26.02.2012 19:03, schrieb Payal:

Have you thought about using a site-to-site ethernet bridge over an OpenVPN tunnel?

It also helps to protect your privacy with regard to the data passend netween laptop and device.

See http://www.openvpn.net/index.php/open-source/documentation/miscellaneous/76-ethernet-bridging.html for a starting point.

HTH,
Thomas

MfG,
Thomas Bätzler

BRINGE Informationstechnik GmbH
Zur Seeplatte 12
D-76228 Karlsruhe
Germany

Fon: +49 721 94246-0
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For starters openvpn might be an overkill. It might make the problem more complex. Any easy solution?

Thanks a lot.

Payal