Finisar Surveyor manual Icmp Destination Unreachable

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User’s Guide

ICMP Destination Unreachable

ICMP Destination Unreachable is a counter of all ICMP destination unreachable errors over a period of time per segment. A count of all destination unreachable ICMP symptoms displays in the Overview counters of Expert View. A threshold for this counter can be set in Expert Alarms for all destination unreachable ICMP errors.

The following types of destination unreachable ICMP errors are counted:

Network Unreachable, Host Unreachable, Protocol Unreachable, Port Unreachable, Fragmentation Needed [D/F Set], Source Route Failed, Destination Network Unknown, Destination Host Unknown, Destination Network Access Denied, Destination Host Access Denied, Network Unreachable for TOS, Host Unreachable for TOS, Destination Unreachable (catches all other Destination Unreachable Errors)

Expert Symptom

ICMP Destination Unreachable is also an expert symptom, and has its own Diagnostic Details. However, this expert symptom reflects only those destination unreachable conditions which cannot be assigned to one of the other destination unreachable symptoms defined above.

ICMP Destination 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 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 is unreachable.

3.If the packet needs to be fragmented and the “don’t fragment” flag is set the host/router will send this message.

4.The source may have an incorrectly configured subnet mask.

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