R.Wieser  wrote:
> Hello all,
>
> I've got a few computers in seperate subnets which I do not allow to
> communicate with each other.
> When I need to transfer data between computers in those subnets I use an USB
> stick.
>
> Somehow my thoughts went to if it would be possible to use an RPi 3B+ as a
> kind go-between.
>
> The first problem would be that I would need to add another (or more)
> ethernet connection (so the 'puters on one subnet cannot reach 'puters on
> the other one).  Is that at all possible (at a usable speed) ?
>
> The second would be to how to transfer data from one subnet to the other.
>
> For that I could imagine a kind of "post office" solution, where 'puters on
> both subnets can leave messages for each other and ofcourse read each others
> replies, but never directly talk to each other.  (both 'puters connect to a
> known port on the RPi).
>
> Does anyone know if such a sulution or project (and tutorial?) for such a
> thing exists ?
>
It's quite easy to configure ssh to do this sort of thing, if you put
the configuration in ~/.ssh/config then the actual command line to do
it can be quite straightforward.

Since rsync uses ssh by default as its transport machanism once you
have ssh set up to do this rsync will work as well so you can copy
files with rsync.


I have incoming ssh connections to my home system set up like this,
the firewall on my home system only allows incoming ssh from a
specific IP address so when connecting from the outside world I first
have to ssh to the 'bridge' system (the one with the specific IP
address) and then from there to my home system.  To facilitate this I
have the following (well, changed a bit to protect the innocent!) in
~/.ssh/config :-

    host home
        ProxyCommand ssh bridgesystem.co.uk nc -q0 homesystem.co.uk 22

bridgesystem.co.uk is the intermediate bridge system which has the IP
address allowed to connect to my home system homesystem.co.uk.  I have
just a user ssh account on bridgesystem.co.uk.

When I connect I just get asked for two passwords, one after the other.

--
Chris Green
·

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