On 23/06/2020 06:34 pm, 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 ?
>
> Regards,
> Rudy Wieser
>
>

Assuming that everything is internal, and you don't have massive
security issues, why not try ftp (vsftpd is good). Set up 2 network
ports, one for each network - one internal, one wifi (or, better, usb).
Make sure you have forwarding off. You could put some iptables rules to
limit filter inputs.

Set up /var/ftp/pub where anyone can drop the file(s) of interest - from
either network and run a cron job to check for differences in the file
list of /var/ftp/pub. Use a nullmailer then to send an email message to
all the possible recipients saying something like fileXYZ is available
for pickup. Note: you need an mua and mta or the receiving machines.

You could have several directories, each associated with either a
sending computer or a sending user and/or a receiving computer/user.


--

Chris Elvidge, England

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