[SNMP4J] Snmp v2 invalid community string

[gangadhar katakam]

Hi Frank,

Thank you for your quick reply. 
If the request gets timeout, will i get null pdu in the response or any error 
message like as shown in the point no:4? - as per the below example in my 
earlier reply.

I just went through the snmp standard, it says "authorizationError" when we send 
wrong community string. 
Please let me know the expected behavior.


I tried with SNMP V3 credentials. I just want to explain all possible scenarios 
so that it might be useful for all other audiences.

1) If we send an Invalid V3 username?
Ans: I am getting an ReportPdu in the TableEvent with [1.3.6.1.6.3.15.1.1.3.0 = 
1] i.e. usmStatsUnknownUserNames.

2) If we send authentication password less than 8 characters?
Ans: USM passphrases must be at least 8 bytes long (RFC3414 §11.2)

3) If we send invalid authentication password?
Ans: Getting an ReportPdu in the TableEvent with [1.3.6.1.6.3.15.1.1.5.0 = 1] 
i.e. usmStatsWrongDigests.

4) If we send invalid Privacy password?
Ans: Getting an ErrorMessage in the TableEvent with "Request timed out". Here as 
it is also a wrong digest, shall we get usmStatsWrongDigests instead of timing 
out?

Please correct me if i am wrong.

Thanks & Regards,
Gangadhar.Katakam



________________________________
From: Frank Fock <fock at agentpp.com>
To: snmp4j at agentpp.org
Sent: Fri, December 3, 2010 7:56:34 AM
Subject: Re: [SNMP4J] Snmp v2 invalid community string

Hi,

The SNMP standard requires that a message
with a wrong community is not answered by
the agent at all.
Thus, you will always get a timeout.

Best regards,
Frank

On 02.12.2010 11:03, gangadhar katakam wrote:
> Hi,
>
> I have written sample to code to fetch data from switch using snmp v2 
community
> string. I gave correct community string, i am able to get the data but if i 
>give
> wrong community string, i am not getting proper error. is it an expected
> behavior?
>
> I am expecting either an exception or response with invalid community string 
>oid
> and its value in the response i.e. [1.3.6.1.6.3.6.1.2.3.0]. but i am not 
>getting
> any of the above said items.
>
> Please let me know the expected behavior.
>
> Here is the sample code i am using:
>
>
>
> Address targetAddress = GenericAddress.parse("udp:10.31.88.93/161");
> TransportMapping transport = new DefaultUdpTransportMapping();
>                          PDU pdu = new PDU();
> Snmp snmp = new Snmp(transport);
> CommunityTarget target = new CommunityTarget();
> target.setVersion(SnmpConstants.version2c);
> target.setAddress(targetAddress);
> target.setCommunity(new OctetString("private12"));
> transport.listen();
>
> pdu.add(new VariableBinding(new OID("1.3.6.1.2.1.2.1.0")));
> pdu.setType(PDU.GET);
>
> ResponseEvent response = snmp.get(pdu, target);
> PDU pduResponse = response.getResponse();
> System.out.println("pdu response:::"+pduResponse);
> Vector vbs = pduResponse.getVariableBindings();
> System.out.println("Variable Bindings:::"+vbs);
>
> Thanks&  Regards,
> Gangadhar.Katakam
>
>
>
> _______________________________________________
> SNMP4J mailing list
> SNMP4J at agentpp.org
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