There are multiple client programs that periodically connect to a port on my server and send a single line of text.

When a connection to the port is made I need to start a PHP CLI script that processes the data. There may be many of the remote scripts running/connecting at more or less the same time so I think it would be best if socat forked a process for each connection to run the script.

I've gotten socat to do most of what I need, using the command

socat tcp-l:myport,fork exec:mypath/socatTest.php

I can read the input on php://stdIn. All is good.

The problem is that the process doesn't seem to fork, so if a second external program sends data while another is doing the same it gets a connection refused error.

Where have I gone wrong?