hello, i have written a basic udp instant messenger program and am trying to send udp packets across the external network, the packets that are sent (from my friends computer to mine) are being dropped at the hub/router. i know this because the little light flashes each time a packet is recieved, however, it is not being routed to the machine. . some network analysis shows that the packet is not being sent from the router to the internal network at all, it is being dropped at the router....where am i going wrong???????

Any help would be greatly appreciated

ps the software works fine on the internal network so this is not a fault with the programming as such