Added unexpected config on 6506E and cannot get MIB on SNMPv2

[hono]

Catalyst6506E  "IOS15.1(2)SY" Line card on slot1 was replaced via OIR due to failure.
then, added ”wr mem”
after that it had been under normal operation,
after router was reloaded for maintenance, SNMPv2 have not been able to get MIB.
And unexpected config was added automatically. See below.
snmp-server engineID local 8000000XXXXXXXXXXXXXXXXX

I didn’t  add any setting on config.
Why isn’t MIB got.
Why does engineID popped up.

SNMP manager and agent are only SNMPv2c.

Please some help.

[marce1000]

 - Try removing this command  (....engineID...) as it is not really needed; or try changing or adding a new snmp community (name) and do dome tests with it. 

Appendix : check the info below obtained from this link :

https://www.cisco.com/en/US/products/ps6017/products_command_reference_chapter09186a008087ab29.html#wp1010373

The SNMP engine ID is a unique string used to identify the device for administration purposes. You do not need to specify an engine ID for the device; a default string is generated using Cisco's enterprise number (1.3.6.1.4.1.9) and the mac address of the first interface on the device. For further details on the SNMP engine ID, see RFC 2571.

If you wish to specify your own ID, note that you need not specify the entire 24-character engine ID if it contains trailing zeros. Specify only the portion of the Engine ID up until the point where only zeros remain in the value. For example, to configure an engine ID of 123400000000000000000000, you can specify snmp-server engineID local 1234.

Changing the value of snmpEngineID has important side-effects. A user's password (entered on the command line) is converted to an MD5 or SHA security digest. This digest is based on both the password and the local engine ID. The command line password is then destroyed, as required by RFC 2274. Because of this deletion, if the local value of engineID changes, the security digests of SNMPv3 users will be invalid, and the users will have to be reconfigured.

Similar restrictions require the reconfiguration of community strings when the engine ID changes. A remote engine ID is required when an SNMPv3 inform is configured. The remote engine ID is used to compute the security digest for authenticating and encrypting packets sent to a user on the remote host.

M.

[homi]

Hello,M

Thank you for your prompt reply.

Unfortunatly, I have already known what you mentioned, sorry about that.

My question is simple.

/MIB became not able to been got on SNMPv2c. Is this bug or not?
/unexpected engineID popped up. Is this bug or not?
Please answer these 2 question.
If it is bug, please put remarks on the "bug search".
it have already affected our customers, we should convince customers of this issue

[marce1000]

  - More fundamentally I would advice to remove and re-add the 6506E from/to your snmp manager software (tool). Check whether this helps.

M.

[homi]

Hello, M

Thanks for your advice.
But this issue was detected on the productive environment.
then I reproduced same symptoms when verified it.
snmp manager software (tool) was different from productive environment and verification environment.
Catalyst6506E "IOS15.1(2)SY"were used in both of environment.
Let me share information,  I'll send you verification data later.


Regards;
hono

[homi]

Hello,M

Let me share attached file.
I verified the data.

Refer to the no.3 on the excel file, after Cat6506E was rebooted, suddenly "snmp-server engineID local 800000090300XXXXXXXXXXXX" come out on the config, even we have never set engineID.
And it has become not able to get MIB.

As for now, we are 100% suceed in reproducing these symptoms.
Could you verify these results.
Most important thing for us is to get concrete statement.
If it is bug, please add remarks on "bug search", if not, please add remarks on "specification".

Thanks for your cooperation.

Regards;

[marce1000]

 - It's not a bug ; the insertion of certain line-card-types will lead to this result ;as stated before , remove and re-add the switch from your snmp manager tool. Check whether this helps.

M.

[homi]

Thanks, Regards;Would you share me the article written about certain line-card-types?
ine cards I tried to verify were WS-X6824-SFP,WS-X6848-GE-TX,WS-X6816-10GE.

following your advice, I removed and re-added several times
, but it didn't work.

Would you verify it?

Thanks, Regards;

[homi]

Hello, M
Have you found someting new?
I hope to reply from you.
Regards;