Hello Simon,

thanks for your reply.

I have found the evildoer.

After installing SLES 12 without a network and execute "dmesg | grep ixgbe", I got the following
message:
failed to load because an unsupported SFP+ or QSFP module type was detected.

The IT stuff (external data center) changed the module and now dmesg shows me the following
Intel(R) 10 Gigabit Network Connection
registered PHC device on eth2
eth2: detected SFP+: 5
eth2: NIC Link is Up 10 Gbps, Flow Control: RX/TX

It was a hardware problem and it is solved.

Thank you that you've worked on this.
Simone