Network Card Diagnostics

[Mynor Aguilar]

I have a server DL380 that reports 3 or 4 "Network adapter link down" on IML 3 or 4 times a day, it loses connectivity almos for 3 or 4 minutes every time. My client says that their catalyst cisco switch is being monitored (no problems detected) and that the NIC is damaged. I have already tried to use a different port on the switch and a new cable, but the problem persist. I ran insight diagnostics from smartstart but it doesnt make any test to the NIC. Is there a tool to make a diagnostic to the server? do u have any other ideas how to determine is it is a problem on the network or the NIC?
Thanx