[SNMP4J] EngineID problem

[Frank Fock]

Mark,

The engine ID of the agent is not stored persistently
by default (it should be hard set or the result of
a fixed computation).

When using SNMPv2c or SNMPv1, the community is mapped
using the SNMP-COMMUNITY-MIB to a security name and
context engine ID of the v3 security model.
Here the problem seems to be originated. I hope this
helps to find the cause.

Best regards,
Frank

Mark Gorokhov wrote:
> BTW, it's plain SNMPv2/public.
> 
> I did not dive into persistent storage details 
> but these are exact steps to reproduce the problem.
> 
> It's possible that there is a bug in my code. It's not clear why
> removing snmp4j persistency storage and restarting the application fixes
> the problem. This means (for me) that persistency storage knows
> something about old EngineID and prevents work with new one.
> 
> -mg
> 
> -----Original Message-----
> From: Frank Fock [mailto:fock at agentpp.com] 
> Sent: Tuesday, October 09, 2007 3:32 PM
> To: Mark Gorokhov
> Cc: SNMP4J at agentpp.org
> Subject: Re: [SNMP4J] EngineID problem
> 
> Hi Mark,
> 
> Are you really sure that the engine ID is
> 
> (a) stored in persistent storage by the agent
> (b) it is modified while restoring the persistent storage?
> 
> That the MIB browser times out after an engine ID
> change is normal and wanted.
> 
> Best regards,
> Frank
> 
> Mark Gorokhov wrote:
>> Steps to reproduce the problem:
>> 1. Start application with SNMP4J agent with EngineID
>> "00:00:00:00:00:00:00:00:02"
>> 2. MIB browser displays managed objects from the application.
>> 3. Close the application (not kill!) This will create SNMP4J
> persistency
>> storage.
>> 4. Start the same application with modified EngineID
>> "00:00:00:00:00:00:00:00:03"
>> PROBLEM: MIB browser timeouts to display managed objects from the
>> application.
>>
>> The problem is fixed after persistency storage is deleted.
>>
>> How to load SNMP4J persistency storage and not to break EngineID?
>>
>> -mg
>>
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> 

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