Problems working thru "Using Triple-Speed Ethernet on DE2-115 Boards"

Hi Every one I will be lucky If any one still following the post and reply to my question

Did any one try to sniff the packets between eth0 and eth1 by connecting a hub between them , cause when I tried doing so , I didn't receive any frames from the terminal , i had to connect eth0 with eth1 directly with no intermediate devices, can any one advice me why it doesn't work when i connect a hub , thanks and appreciate your help