Replaced defective Tyan-double-opterons server mainboard with a minimal asus H81M-K-intel i3, maintaining the same two mirror-raid HDs with debian amd64 wheezy.
Now, network is only establised at a ZyXEL router when loading gnome, thereafter slogin to my amd64 server occurs regularly. Before that, at the linux prompt, no network with the H81M-K. Command