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Chapter 5 77

Troubleshooting

Adapter cannot communicate

with other hosts on the local

network.

• Use fddilink to verify that upstream and

downstream neighbors are correct.

• Examine the LEDs.

• Check the FDDI cable. Make sure the FDDI media is

correctly installed. ping the failed system from

another host on the network.

• Distinguish between an unknown host, which

indicates a /etc/hosts ﬁle problem; and a

non-response, which usually indicates a routing

problem.

• Check the arp table with arp -a.

(Dual-ring only) Adapter can

only communicate with a

subset of hosts on the local

network.

• See above.

• Check for “twisted ring” (port A cabled to port A or

port B cabled to port B). Visually inspect the cabling.

Or, check the syslog ﬁle (default is

/var/adm/syslog/syslog.log) for a message like

the following: Undesired Connection Attempt: A ->A.

• Check for link failures. Run fddilink on local and

remote systems and check for “WRAP_A” or

“WRAP_B” CFM states.

Symptom Action