Finisar Surveyor - Manual (Page 278)

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Surveyor
User’s Guide
ICMP Host Unreachable
Counter
ICMP Host 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 Host 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 Host 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 destination host 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 host is truly unreachable (no action required).