PHP stream socket server

Question

I have a PHP server listening on port 5001 and 127.0.0.1

$socket =  stream_socket_server("$host:$port", $errno, $errstr)

It work fine when a client in php connects to the server, but the same fails if a client written in C tries to connect.

I have updated firewall settings, just unable to resolve the issue. Is there a different way to handle incoming connections from a C client.