I have to test a homebrew server that accepts a lot of incoming TCP traffic on a single port. The protocol is homebrew as well.

For testing purposes, I'd like to send this traffic both : - to the production server (say, listening on port 12345) - to the test server (say, listening on port 23456)

My clients apps are "dumb" : they never read data back, and the server never replies anyway, my server only accepts connections, and do statistical computations and store/forward/service both raw and computed data.

Actually, client apps and hardware are so simple there is no way I can tell clients to send their stream on both servers... And using "fake" clients is not good enough.

What could be the simplest solution ? I can of course write an intermediary app that just copy incoming data and send it back to the testing server, pretending to be the client.

I have a single server running Squeeze and have total control over it.

Thanks in advance for your replies.