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.
-j