When running a Spectrum AutoDiscovery, Spectrum is not modeling devices even though the correct community strings are listed in the SNMP Information section of the AutoDiscovery Configuration. For example, in the following snapshot of the of the SNMP Information section of the AutoDiscovery Configuration, the V3 community string is listed first followed by two V1 community strings. There are several devices in the range being discovered that are not configured with the specified V3 community string but are configured with one of the V1 community strings in the list. When the discovery is run, the user expects to see several devices discovered with the V1 community strings but none are discovered.
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When an AutoDiscovery Configuration is run, Spectrum tests the community strings starting with the first community string at the top of the list and works it's way down the list testing until it gets either a response from one of the community strings in the list or all in the list fail. What is happening is Spectrum gets an authentication failure response from the device when using the V3 community string. Spectrum is misinterpreting the authentication failure response from the device as a valid response and does not attempt the other community strings in the list.
If the AutoDiscovery debug is enabled during this discovery, you will see messages similar to the following in the ADISC debug file where Spectrum is attempting to model the device using the V3 community string even though the device at that ip address is not configured with that v3 community string
11:15:12 IP Discovery 184.108.40.206: mtype identification failed at community name #v3/P:AuthPassword:PrivPassword/USER and SNMP port 161 with error: 1
This issue is addressed in the Spectrum 10.00.00.PTF_10.0.012 patch. The following is from the release notes:
Symptom: Discovery incorrectly interpreting SNMP authentication failure responses, resulting in improper modeling.
Resolution: Properly handled SNMP authentication failure responses.
This issue will also be addressed in the 10.00.01.00 release of Spectrum.
this article was originally published as 000032872