do you mean that even the UDP packets with "wrong" destination address are dropped by the wiznet?
Note that "sniffer" applications have become nearly useless since the standard ethernet connection has become a jack into a "switch" (implemented on a chip.) The main characteristic of a switch (vs a "hub") is that packets are only sent to the socket that has the relevant hardware MAC address present...
Unless you happen to have control of the switch, and it's a managed switch. If so you can usually configure the switch to mirror all traffic to a particular port and put your sniffer there.
Please enter a valid email to subscribe
We need to confirm your email address.
To complete the subscription, please click the link in the
email we just sent you.
Thank you for subscribing!
via Egeo 16