Smarts NCM: Is it possible to use NCM to generate a list of duplicate Engine IDs? How are Duplicate SNMP Engine IDs determined in NCM? What could be the impact if two or more devices have same snmp engine id?

Products

• VMware Smart Assurance

Issue/Introduction

Symptoms:


Every device is meant to have a unique Engine ID and if this is not the case, it can cause all kinds of problems, for instance pull config of the device will fail. Duplicate SNMP Engine IDs can cause pull config and discovery to fail

Some customers need to be able to obtain the device SNMP Engine ID in order to determine if they have any devices with duplicate Engine IDs on their system.

Devices with duplicate Engine IDs are non-complaint with RFC 3411 (Ref: http://www.ietf.org/rfc/rfc3411.txt) .
According to the RFC no network device can have the same SNMP V3 engine ID.

Environment

VMware Smart Assurance - NCM

Resolution

There is no mechanism in NCM to see or retrieve all the list of engineIDs. Whenever you do pull or discovery you can see that particular engineID of the device in NCM autodisc logs and commmgr logs. However, here you will see only one engineID this will not help you to identify duplicate engineIDs.

There are 2 workarounds: 

i) Using NCM to find the Engine IDs

The following can be set up via the NCM Gui :

Please note: these steps to be run favorably on v3 devices. Other devices can throw invalid command 

 

1. select the devices in NCM GUI.

2. Rightclick->Editor->Command->terminalComand
3. Enter the device specific command to get the SNMP Engine ID for v3 devices e.g. for some Cisco devices, this command is "show snmp engineid"

4. schedule

5. in Tasks select donot pull

5. run on approve.  

 

You will see the following in the commmgr.log:

 

Jun 17 12:25:49 -311477360/push(100169)#4: show snmp engineid

Jun 17 12:25:49 -311477360/push(100169)#4: Local SNMP engineID: 800000090300001DA2D0ED03

Jun 17 12:25:49 -311477360/push(100169)#4: Remote Engine ID          IP-addr    Port

Jun 17 12:25:49 -311477360/push(100169)#4: Switch167#

This can be scheduled as a job to run on all devices as per user requirements. 

ii) Not using Smarts 

1. Proactively find these devices with the help of your local network admins .
2. Discover them in different networks or different device servers.