Are you in Linux? What Kernel?

I have the same problem when running either my server *OR* my clients off my Linksys Gigabit switch (the original one, not the Cisco rebranded one). I haven't done extensive packet sniffing, yet, but I plan to. I triend a Netgear 4-port Gig switch, and the same problem happened. I tried a plain 10/100 switch, and it worked fine. My router is a Siemens powerline 4-port switch (standard NAT + 4 ports + Powerline capability).

-Dan