Re: netcat missing example (is this even possible?)

[David Burrows <snadge () gmail com>]

Hello again!

Sorry to reply to my own post so soon, but it appears that I have found a
solution that could save someone the trouble of what I just went though.

(on server)
socat /dev/urandom TCP4-LISTEN:9999
(on client - substitute localhost for the servers ip if not localhost)
socat TCP4:localhost:9999 PTY,link=/dev/newrandom,raw,echo=0

The server socat command can be substituted with: ncat -l -k 9999 -c 'cat
/dev/urandom'
I'm not sure if there would be a netcat equivalent of the client connection.
Now you can "dd bs=nnn count=1 /dev/newrandom of=/dev/null" and cat, etc all
works as expected with the newly cloned device.

I'm assuming raw is needed to not process the EOF characters, and echo=0
stops the client from constantly reading from the socket.

This can be useful for boxes in a data centre, or on a network that do not
have a good source of random entropy, to collect that data from a box that
has a proper RNG or a better entropy source.

Regards,

David.

On Tue, Jun 1, 2010 at 11:33 PM, David Burrows <snadge () gmail com> wrote:

> Hi all,
>
> I wish to use netcat to connect /dev/random to a tcp socket, and then
> connect the other end of that socket to a pty device, such that reads from
> the pty device, are tunneled through the tcp socket.  Eg.  Host A ->
> /dev/random -> tcp socket -> ... Host B -> tcp socket -> /dev/newrandom.
> For testing purposes, it is easiest to use /dev/urandom and localhost.
>
> At first it would appear you could use netcat or socat to do this, but if
> baffles me as to how.  I have tried the following with socat, somewhat
> unsuccesfully:
> socat /dev/urandom TCP4-LISTEN:12345
> (in another terminal)
> socat TCP4:localhost:12345 PTY,link=/dev/newrandom,wait-slave
>
> This sort of works, in the sense that I can open /dev/newrandom, and get
> data from it, but the reads return short and the first socat starts
> continuously flooding the tcp socket as long as there is data in
> /dev/urandom (which is always true).
>
> I'm likely going about this entirely the wrong way, which is why I am
> appealing for someone more knowledgeable to point out a better way to
> achieve this?
>
> Curiously,
>
> David.
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