Vista - Vista filters incoming requests from 127.0.0.1

Hi all,

I'm developing a software that connects to an external device through UDP/IP using a cross cable. That device's default IP is 127.0.0.1 (I know this ip is reserved for loopback, but the device is developed by a third party and that's it behaviour). When my software starts, it sends an UDP broadcast "echo" to search any device connected.

My problem comes here: in Windows Vista when the device answers that echo, it sends a packet with ip source address 127.0.0.1, but my software can't receive it. I've checked that it works perfectly in XP, but in Vista it seems to be any sort of ¿security? procedure that filters that incoming packet with src ip 127.0.0.1. It's important to note that firewall is disabled, so the filtering agent seems to be another one.

Do you know anything about this? How could avoid that filtering?

Thanks