Router port forwarding and rtsp streaming problem

I'm using vlcj to stream (RTSP) video. The problem is I am behind a router and dd-wrt only forwards and open ports if there is an开发者_StackOverflow中文版 application that is listening. But, I stream video, I don't listen on ports that are streaming...

How can I get around this problem? Everything works fine if I don't use the router and connect directly.

*info: linksys wrt54gl Firmware: DD-WRT v24-sp2 (10/10/09) min

RTSP uses tcp communication for session control between clients and server. So the server will have to listen for clients. The default port for RTSP is 554, however examples on VLCj use port 5555 so be advised. This port has to be forwarded by the router from the WAN address to the LAN address of the streaming server.

Please don't confuse with RTP which uses multicast instead and broadcast to the LAN broadcast address! Doing broadcast through a router is difficult as it will have to re-broadcast to WAN.