[SNMP4J] TCP Socket in SYN_RECV when sending V3 traps

[Frank Fock]

Hi Neeraj,

Please make sure, that you have understand the engine ID and context 
engine ID terms and usages.
It seems that you mix up things. Your example below cannot work for 
INFORM PDUs, because
you need to specify the authoritative engine ID as context engine ID 
then. This is the
INFORM *receivers* engine ID.
Instead, you use the senders engine ID. The receiver should drop/ignore 
such an INFORM message with
unknownPduHandles counter increased.

Best regards,
Frank

Am 16.06.2017 um 22:41 schrieb Neeraj Vaidya:
> Hi Frank,
> Coming back to this conversation as I have been away from this task due to other project commitments.
> In the example below, I have also noticed that if I change the PDU type to INFORM, the receiving snmptrap collector (which is net-snmp snmptrapd) fails to match the engine id. It picks up something totally different from what I am setting below.
> Is there some other place where I need to set the engineId ?
>
> Regards,
> Neeraj
>
> Sent from my iPhone
>
> On 24 May 2017, at 16:44, Frank Fock <fock at agentpp.com> wrote:
>
>>> ------------------------------------------------ Code Start ------------------------------------------------
>>>
>>>                Address address = GenericAddress.parse("tcp:rhelhost1/1163");
>>>
>>>         try {
>>>             TransportMapping transportMapping = new DefaultTcpTransportMapping();
>>>             transportMapping.listen();
>>>                     
>>>             Snmp snmp = new Snmp(transportMapping);
>>>
>>>             USM usm = new USM(SecurityProtocols.getInstance(),
>>>                                                       new OctetString(MPv3.createLocalEngineID()), 0);
>>>             
>>>             SecurityModels.getInstance().addSecurityModel(usm);
>>>
>>>             //snmp.listen(); ----> Do I need to use this invocation ??
>>>
>>>             byte[] b = (new BigInteger("0102030405",16)).toByteArray();
>>>
>>>             snmp.getUSM().addUser(new OctetString("snmp4j"),
>>>                     new UsmUser(new OctetString("snmp4j"), AuthMD5.ID, new OctetString("snmp4j"), PrivDES.ID, new OctetString("snmp4j")));
>>>             
>>>             UserTarget target = new UserTarget();
>>>                 
>>>             target.setAddress(address);
>>>             target.setRetries(1);
>>>             target.setTimeout(5000);
>>>             target.setVersion(SnmpConstants.version3);
>>>             target.setSecurityLevel(SecurityLevel.AUTH_NOPRIV);
>>>             target.setSecurityName(new OctetString("snmp4j"));
>>>             
>>>             // create the PDU
>>>             ScopedPDU pdu = new ScopedPDU();
>>>             long sysUpTime = Instant.now().getEpochSecond();
>>>             //pdu.add(new VariableBinding(SnmpConstants.sysUpTime),new OctetString(new Date().toString()));
>>>             pdu.setType(ScopedPDU.TRAP);
>>>             pdu.add(new VariableBinding(SnmpConstants.sysUpTime, new TimeTicks(sysUpTime)));
>>>             pdu.add(new VariableBinding(SnmpConstants.snmpTrapOID, SnmpConstants.linkUp));
>>>             pdu.setContextEngineID(new OctetString().fromByteArray(b));
>>>             snmp.setLocalEngine(b, 0, 0);
>>>             // send the PDU
>>>             
>>>             ResponseEvent response = null;
>>>
>>>             response = snmp.send(pdu, target);
>>>
>>>             Thread.sleep(10); // This Sleep somehow allows the entire TCP 3-way handshake to occur without terminating the program
>>>
>>>             snmp.close();
>>>
>>>         } catch (IOException e) {
>>>             e.printStackTrace();
>>>         } catch (InterruptedException e) {
>>>             e.printStackTrace();
>>>         }
>>> ------------------------------------------------ Code End  -----------------------------------------------

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