$> gem install em-proxy
$> em-proxy
Usage: em-proxy [options]
-l, --listen [PORT] Port to listen on
-d, --duplex [host:port, ...] List of backends to duplex data to
-r, --relay [hostname:port] Relay endpoint: hostname:port
-s, --socket [filename] Relay endpoint: unix filename
-v, --verbose Run in debug mode
$> em-proxy -l 8080 -r localhost:8081 -d localhost:8082,localhost:8083 -v
The above will start em-proxy on port 8080, relay and respond with data from port 8081, and also (optional) duplicate all traffic to ports 8082 and 8083 (and discard their responses).