Finisar Surveyor - Manual (Page 283)

10-79
Expert Features
Network Layer
10
ICMP Network Unreachable
Counter
ICMP Network Unreachable events are counted in the ICMP All Errors and the
ICMP Destination Unreachable counters. A count of all destination unreachable
ICMP symptoms and a count of all ICMP errors displays in the
Overview counters
of Expert View. A threshold can be set in Expert Alarms for all destination
unreachable ICMP errors or for all ICMP errors.
Expert Symptom
ICMP Network Unreachable events are automatically logged as expert symptoms.
The
Symptom Summary field provides information about the IP addresses involved.
For example:
[206.250.228.69] cannot be reached by [206.250.228.11].
SA=[206.250.228.11] DA=[206.250.228.69]
Diagnostic Details
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Problem Description:
An ICMP Destination Network Unreachable message has been sent.
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Probable Cause(s):
1. If a router has a routing table problem, it may send this message.
2. A host may send this message if a network is unreachable.
3. The source may have an incorrectly configured subnet mask.
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Recommended Action(s):
1. Check the routing tables of the router that this message was generated from.
2. Check the netmask configuration of the source.
3. Ignore this message if the network is truly unreachable (no action required).