A device capture, credential test, or scan fails with "ERROR: SNMP++: SNMP request timeout" or "Device skipped - no SNMP access".

Tips:

• To check if the issue is specific to Discovery, use snmpwbulkwalk (or snmpwalk if get bulk is disabled).
• When a device capture is affected by this issue, the log in /usr/tideway/var/captures could contain more details about the cause.
• When a scan or a test credential is affected by the issue the outpost logs (or appliance discovery logs) could contain more details about the case. Especially if with the debug log level

Root cause 1: The device affected by the issue (test credential, device capture ...) is unreasonably slow.

To confirm: If the error can be reproduced with snmpwalk, the root cause is possible.
Workaround: Increase the timeout in the SNMP credential to 100 seconds and retry.

Root cause 2: The credential uses snmp v1 or 2 and the snmp community string is incorrect. 

To confirm:

If the operation affected by this issue fails with "Unable to get the deviceInfo: TRANSIENT"  or " SNMP request timeout", the root cause is probable

If the error can be reproduced with snmpwalk, the root cause is possible.

Root cause 3: The device affected by this issue does not accept the snmp version used by Discovery

To confirm: If the error can be reproduced with snmpwalk, the root cause is possible.

Root cause 4: Snmp v3 is used and the scanned agent is configured to not respond to some queries (ACL). 

To confirm: If the error can be reproduced with snmpwalk, the root cause is possible.

Root cause 5: The device affected by this issue is configured to respond using an incorrect gateway (wrong ip configuration).

To confirm: If the error can be reproduced with snmpwalk, the root cause is possible.

Root cause 6: Undocumented Hitashi defect in HNAS (Hitachi NAS) storage device.

To confirm: If the error can be reproduced with snmpwalk, the root cause is possible.
Workaround: Configure the device to use the "out of the box IP"

Root cause 7: Problem linked to the usage of getNext/getBulk SNMP methods

To confirm: If the error can be reproduced with snmpwalk, the root cause is possible.
Workaround: In the SNMP credential, change the status of the check box "Use GETBULK"

Root cause 8: The length of the Privacy Key (Snmp v3) is too long

To confirm: If the error can be reproduced with snmpwalk, the root cause is possible.