Entry level server systems based on the S1200BTL (ATX) or S1200BTS (uATX) system boards can loose second LAN port functionality. The LAN port is not detected in the operating system; it is not available in device manager.
This issue should only occur if you have recently completed one of the following:
In these instances the second LAN controller can be disabled due to a BIOS problem. You will need to manually re-enable the second LAN controller.
The root cause is a BIOS glitch that Intel have documented. Their resolution is described below.
Ensure both controllers are enabled in the BIOS:
Note: If both LAN controllers are enabled in the BIOS and still one controller is missing in the operating system, or if the LAN controller repeatedly disappears even though you have not met the circumstances in the Issue section, then please contact Stone for warranty service.