Open same UDP port from multiple applications

Question

I need to write to a local UDP port from one application, and read from that same UDP port from another application. (We're doing two-way communication, but use one port to send from A to B, and another port to send from B to A.) One of the applications is written in C++, and the C++ UDP open includes ReuseAddress in the socket options; there seems to be no way to specify this functionality from LV. Note that these applications are deployed to a Vista (64-bit) system with the LV Runtime (not the LV development environment).
This used to work when we were using LV 8.5 (as long as we ran the LV application before running the C++ application), but when we updated to LV
8.6.1 it no longer works -- the second application to be run cannot open the UDP port.
Sometimes the applications are run on different machines, and then everything works fine. But sometimes we need to run both applications on the same machine, and then we encounter this problem. So whatever solution we come up with, we need to be able to make it work in both configurations (same machine, or different machines).

Answer 1

I discovered that I can open any port (e.g., 0, and let it allocate a port for me), and then write to the port I want to write to with no problems, bypassing the problem.