New to pfSense / Network problems

[jah]

Hi,

I made a fresh pfSense install on my mini ITX device.
The motherboard is:
http://linitx.com/viewproduct.php?prodid=11212

I noticed a strange behavior of pfSense.

Install was ok.
Then when it boots, I can browse 192.168.1.1 from my LAN PC and Internet sharing is OK.
After some time (approx 5-10 mn) I can see Ubuntu's Network Manager shows quickly a disconnected message and then goes back to the connected state.
I keep the DHCP IP offered by pfSense, but I cannot reach the webGUI nor Internet.

To get everything working again, I have to go on the router itself (I have VGA and keyboard on it) and do a Assign Interfaces. I set everything the same, it reloads and after that I am ok for an other 5-10 min.

The NIC i have are 2x Realtek RT8110SC 10/100/1000 LAN.

What should I do ?

At the same time, I have a D-Link DWA 547 (Atheros AR5008) which is supposed to be supported but that does not appears in my interfaces list.

I don't know yet how to update the distro or install a driver.

Please help me.

Thanks,