Port Unreachable

Hi Guys

I have a simple UDP communications set up where I open up a UDP Port on the RCM6710 using:

udp_open(&sock, LOCAL_PORT, REMOTE_IP,0, NULL)

I specify an IP Address and port to listen too. I then call TCP_TICK regularly and it works great communicating with a Visual Basic programming running on my PC.  The problem comes when I halt the VB program and restart it. When I restart the VB program and try to send data to the Rabbit I get no reply from the rabbit (rabbit never receives the packet) and using a packet sniffer I see that I get an error packet saying the "Port is unreachable". The only way to correct this is to close the and reopen the socket on the rabbit. 


I have checked the return values on TCP_TICK and ifstatus and they are both nonzero indicating that as far as the rabbit is concerned the connection is still good.

Is there a way I can check on the rabbit that everything is OK and reset it if it is not?

Thanks