XP blocking UDP ports?

[C Delaney]

I have an application I use that uses UDP ports in the
501xx range to communicate with external devices. Running
Windows 2000, this application runs perfectly fine.
However, now that I am running XP Pro, the application
fails to receive the packets destined for the UDP ports.
Using Ethereal, I can see that the packets are arriving at
my laptop, but the application fails to receive them. My
only conclusion is that XP is somehow blocking these
packets from entering the system. I have poured through
all of the security settings on my machine and have yet to
find a difference between my 2000 machine and XP machine.
I do not have the firewall enabled, and IP filtering is
turned off. Does anyone know why this might be
happening? Is there some way that I can allow access to
these UDP ports?

Thanks for any assistance you can offer.

 

[David Jones]

With no firewall or filtering enabled, XP does not block
UDP ports. Unfortunately, without being able to debug
what exactly the application does, it's hard to give you
a good answer with just this information.