Dsniff not sniffing properly

[Hari Sekhon <hpsekhon () googlemail com>]

Hi,
  I have dsniff on 2 linux laptops, one Debian, one Gentoo and it works 
fine, if I run it on the local machine and then from the same machine 
log in to a remote ftp server on my local network as a test it sniffs 
the authentication pair and displays it.

However, I have it on another workstation (Gentoo Linux) and if I run 
dsniff as root, it starts sniffing on eth0, my only network interface 
and the one I am connected to my lan through. I then log in to the same 
ftp server again and it remains blank.

# dsniff
dsniff: listening on eth0
<lots of nothing here>

Even after I log out of the ftp server there is still nothing (upon 
logout is when it usually displays the creds to me)

So the question is, what is wrong with dsniff on my workstation?
lspci says I have the following network card:

04:00.0 Ethernet controller: Broadcom Corporation NetXtreme BCM5754 
Gigabit Ethernet PCI Express (rev 02)

Is the network card somehow crippled to prevent this? (In which case 
there should be mass boycott of this card)

It doesn't even need to be in promiscuous mode in order to sniff from 
the local machine. Why is it not working?

--
Hari Sekhon