About Diagnosing Specific Problems - Sun Microsystems Enterprise 250 Owner's Manual

About Diagnosing Specific Problems

Network Communications Failure
Symptom
The system is unable to communicate over the network.
Action
Your system conforms to the Ethernet 10/100BASE-T standard, which states that the
Ethernet 10BASE-T link integrity test function should always be enabled on both the
host system and the Ethernet hub. The system cannot communicate with a network
if this function is not set identically for both the system and the network hub (either
enabled for both or disabled for both). This problem applies only to 10BASE-T
network hubs, where the Ethernet link integrity test is optional. This is not a
problem for 100BASE-T networks, where the test is enabled by default. Refer to the
documentation provided with your Ethernet hub for more information about the
link integrity test function.
If you connect the system to a network and the network does not respond, use the
OpenBoot PROM command watch-net-all to display conditions for all network
connections:
ok watch-net-all
For most PCI Ethernet cards, the link integrity test function can be enabled or
disabled with a hardware jumper on the PCI card, which you must set manually.
(See the documentation supplied with the card.) For the standard TPE and MII main
logic board ports, the link test is enabled or disabled through software, as
shown below.
Remember also that the TPE and MII ports share the same circuitry and as a result,
only one port can be used at a time.
254 Sun Enterprise 250 Server Owner's Guide • June 1998