passing data transparently

passing data transparently

[Payal]

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

Re: passing data transparently

[Thomas Bätzler]

Am 26.02.2012 19:03, schrieb Payal:
> 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
>

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
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Re: passing data transparently

[Payal]

On Sun, Feb 26, 2012 at 07:36:06PM +0100, Thomas Bätzler wrote:
> Have you thought about using a site-to-site ethernet bridge over an OpenVPN
> tunnel?

For starters openvpn might be an overkill. It might make the problem
more complex. Any easy solution?

Thanks a lot.

Payal