I have 2 PC under linux (Ubuntu 10.04). Hardware must be exactly the same, software is the same (same installation procedure). I have also check BIOS configuration, there is no difference.
On one machine, lshw -c network give :
...
  *-network               
       description: Ethernet interface
       product: 82566DM-2 Gigabit Network Connection
       vendor: Intel Corporation
       physical id: 19
       bus info: pci@0000:00:19.0
       logical name: eth1
       version: 02
       serial: 00:XX:XX:XX:XX:XX
       width: 32 bits
       clock: 33MHz
       capabilities: bus_master cap_list ethernet physical
       configuration: broadcast=yes driver=e1000e driverversion=1.0.2-k2 firmware=1.3-0 ip=192.168.0.26 latency=0 multicast=yes
       resources: irq:31 memory:fcf40000-fcf5ffff memory:fcf7a000-fcf7afff ioport:c880(size=32)
And I can see all my interface network on this machine.
On other machine, It's give :
 *-network UNCLAIMED     
       description: Ethernet controller
       product: 82566DM-2 Gigabit Network Connection
       vendor: Intel Corporation
       physical id: 19
       bus info: pci@0000:00:19.0
       version: 02
       width: 32 bits
       clock: 33MHz
       capabilities: cap_list
       configuration: latency=0
       resources: memory:fe840000-fe85ffff memory:fe87a000-fe87afff ioport:c880(size=32)
On this second machine, I don't see this network interface.
With this diagnostics, can I declare that second hardware have a defect, or it exist other diagnostics tools, to found configuration trouble ?
Best regard Emmanuel