Guruplug network slow?

Ok. Now I was able to test this with onother computer. The guruplug was definitly not the problem.

Hi, I have a guruplug server plus, plugged two ethernet cables in. Both at 100Mbits.
I recogniced sending files over to the plug is something slow, so I measured the speed of the connection. What I did is:

This is sending data from computer to plug:

Code:

myplug# netcat -l -p 12345 >/dev/null

Code:

mycomputer# netcat myplug 12345 -c "dd if=/dev/zero count=10000"
10000+0 Datensätze ein
10000+0 Datensätze aus
5120000 Bytes (5,1 MB) kopiert, 12,6162 s, 406 kB/s

This is sending data from plug to computer:

Code:

mycomputer# netcat -l -p 12345 >/dev/null

Code:

myplug# netcat mycomputer 12345 -c "dd if=/dev/zero count=10000"
10000+0 Datensätze ein
10000+0 Datensätze aus
5120000 Bytes (5,1 MB) kopiert, 0,420065 s, 12,2 MB/s

So, 12,2 MB/s (plug->computer) seems normal. But 406 kB/s (computer->plug) is far too slow.
The question now is:
What causes this slowness? Is it because of the plug/ethernet driver, or is it caused by other hardware in my network?
Could someone of you please repeat this measurement and post the result and configuration (10/100/1000 Mbit? 1 or 2 cables plugged in?) here?

Something also useful:

Code:

myplug# uname -a
Linux nomainframe4u 2.6.33.2-00003-g4b82fc0 #1 PREEMPT Thu Apr 22 03:29:35 PDT 2010 armv5tel GNU/Linux
myplug# grep "link up" /var/log/messages | tail -n 2
May 27 16:52:20 nomainframe4u kernel: eth0: link up, 100 Mb/s, full duplex, flow control disabled
May 27 16:52:21 nomainframe4u kernel: eth1: link up, 100 Mb/s, full duplex, flow control disabled