When you install Microsoft Windows (any version) or Microsoft Windows Server (any version) on a system that has two identical network adapters installed, the association between the network adapters that are identified in Device Manager and the Local Area or Ethernet Connections that are identified in Network Connections may be reversed. For example, network adapter number 1 may be associated with Local Area Connection 2 (Ethernet 2 in later editions) and network adapter number 2 may be associated with Local Area Connection (Ethernet in later editions).
Note This issue does not occur with the computers that have Consistent Device Naming (CDN) enabled in BIOS.
During Windows Server installation, hardware detection is performed during the initial portion of Setup. The order in which devices are detected is not guaranteed, and the order can change to optimize any platform or for any other reason that affects the timing. Since connection names get assigned to adapter names in the order they appear in the OS, the connection name to adapter name mapping may be modified from boot to boot.
To work around this problem, rename the Local Area Connections that are listed in Network Connections.
In Windows 8 (Windows Server 2012) and later editions of Windows and Windows Server, the computer manufacturer has the opportunity to identify the NICs in a vendor-specific naming scheme through the BIOS. If this feature, known as Consistent Device Naming, is installed, the variable name mapping won’t occur.