No error on Vista when using sendto function.

Hello

When I try to send an UDP packet on Vista with sendto function and I unplug my internet cable
I DO NOT get an error. When i send it on WINXP i get host unreachable as expected.
What should I do to fix this problem on Vista?

Thank you for your replys,
Peter.

Didnt i write my problem clear enough?

Perhaps ask in the Win32 section: http://www.codeguru.com/forum/forumdisplay.php?f=47