When doing deployment on modern ultrabooks or devices like Microsoft Surface, no ethernet adapter is build in. You must use external adapters by using USB connected to have the same behavior. When using multiple cables however, or using the same ethernet adapter for multiple devices, ConfigMgr is going crazy. When that happens it's good to know that SMBIOS GUID's can be used as well instead of using a MAC address. Let's have a read on that one.
The MAC address of a network interface is its unique identifier. Think of it as the serial number of that network interface. When switching network interfaces between devices, MAC addresses wil change also. Therefore we need a SMBIOS GUID. ConfigMgr 2012 uses SMBIOS to identify computers, and falls back to MAC addresses if SMBIOS information is not available. SMBIOS is the GUID that is stored in the Device’s BIOS or UEFI. It’s unique to the device and ConfigMgr uses it to recognize prestaged computers.
When importing systems in ConfigMgr, a computer name and MAC address or SMBIOS GUID must be filled in. MAC addresses can be found in command prompt when typing in "ipconfig /all". SMBIOS can be found in BIOS or by typing in "wmic csproduct get uuid". After re-deployment, where I switched network interfaces, the correct computer name was still used. So when using SMBIOS instead of MAC, it's allowed to switch network interfaces. Good news!
When importing of many new systems is needed, just ask your hardware vendor for a list of SMBIOS GUID's. That way it's easy to import them in ConfigMgr, and prevent MAC address isues. For example: SurfacePro3, 00:1E:8C:17:F0:E5, 3164B0C0-AB47-11DC-A63B-001E8C17F0E5 (for usage in a CSV file). The future is bright, ConfigMgr is still in lead on this one ;)
For more information, have a look on: Microsoft blogs