Lenovo ThinkSystem SR665 V3 User Manual page 508

• Make sure that the cable rating is sufficient for the data rate of the network. For example, a 1 Gb
RJ45 network requires a cable of Cat5e or higher rating.
Step 3. Determine whether the switch supports auto-negotiation. If not, try configuring the integrated
Ethernet controller manually to match the speed of the switch port. Also, if forward error correction
(FEC) modes are supported, make sure that both the adapter and the switch port have matching
settings.
Step 4. Check the Ethernet controller LEDs on the server. These LEDs indicate whether there is a problem
with the connector, cable, or switch.
If the Ethernet function is implemented on the system board assembly, the Ethernet controller LED
locations are specified in
• The Ethernet link status LED is lit when the Ethernet controller has established link with the
switch port. If the LED is off, there might be a defective connector or cable or a problem with the
switch port. In some cases, a bi-color link LED is used. Green indicates a link at the highest
network speed. Yellow indicates a link lower than the highest network speed.
• The Ethernet transmit/receive activity LED is lit or blinks when the Ethernet controller sends or
receives data over the Ethernet network. If the Ethernet transmit/receive activity is off, make sure
that the switch is powered on, the network is operating, and the correct device drivers are
installed.
Step 5. Check for operating-system-specific causes of the problem, and make sure that the operating
system drivers are installed correctly.
Step 6. Make sure that the device drivers on the client and server are using the same protocol.
If the Ethernet controller still cannot connect to the network but the hardware appears to be working, the
network administrator must investigate other possible causes of the error.
ThinkSystem SR665 V3 User Guide
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"Troubleshooting by system LEDs and diagnostics display" on page 476.