Some of the other processes in this project already use POE and I am familiar with it. This process is just to mimic an expensive piece of hardware at this stage and as far as I can see it simply boils down to:

@pool = (1..N);
listen on port N
loop {
  select(waiting for connect);
  accept
  pick port from pool
  fork
    child does connect, reads socket, writes to forwarder
      socket, reads results and writes back to client.
      closes sockets and exits.
    parent looks for dead children to add port back to pool
}
[download]

and POE seems a bit of an overkill for this. Guess I'll knock up the above first.