IBM eServer 445 xSeries Hardware Maintenance Manual And Troubleshooting Manual page 87

If the problem still exists after checking the operating system documentation, try the
following:
v Make sure that the cable is installed correctly.
The network cable must be securely attached at all connections. If the cable is
attached but the problem remains, try a different cable.
If you set the Ethernet controller to operate at 100 Mbps, you must use Category
5 cabling.
If you directly connect two workstations (without a hub), or if you are not using a
hub with X ports, use a crossover cable.
Note: To determine whether a hub has an X port, check the port label. If the
label contains an X, the hub has an X port.
v Determine if the hub supports auto-negotiation. If not, try configuring the
integrated Ethernet controller manually to match the speed and duplex mode of
the hub.
v Check the Ethernet controller lights on the server rear panel.
These lights indicate whether a problem exists with the connector, cable, or hub.
– The Ethernet Link Status light illuminates when the Ethernet controller
receives a LINK pulse from the hub. If the light is off, there might be a
defective connector or cable, or a problem with the hub.
– The Ethernet Transmit/Receive Activity light illuminates when the Ethernet
controller sends or receives data over the Ethernet Network. If the Ethernet
Transmit/Receive Activity light is off, make sure that the hub and network are
operating and that the correct device drivers are loaded.
v Check the LAN activity light (if available) on the rear of the server. The LAN
activity light is illuminated when data is active on the Ethernet network. If the
LAN activity light is off, make sure that the hub and network are operating and
that the correct device drivers are loaded.
v Make sure that you are using the correct device drivers, which are supplied with
the server.
v Check for operating-system-specific causes for the problem.
v 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, inform the network
administrator.
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Chapter 3. Diagnostics