Are there any Full duplex Ethernet HUB ?
Is it possible to have a full duplex Hub? Answer is NO. The Hub always works in Half duplex mode. And if it says 100 Mbps full duplex then probably its switch not hub.
If you want to sniff the packets using HUB, go for real hub ( 10 Mbps) . The hub actually sends all traffic to all ports but switches and Dual speed Hub can be little picky in traffic.
Hubs can work in either 10 Mbps or 100 Mbps but always in half duplex mode.
http://wiki.wireshark.org/HubReference for more details.