[SNMP4J] TCP Socket in SYN_RECV when sending V3 traps

[Neeraj Vaidya]

Thanks Frank. So how do I get the authoritativeEngineId at runtime ?

The remote snmptrap collector has provided me with a user id of myuser and engine id of 0102030405. This is via an email correspondence which I had with the administrators of the remote system.

When I use the SnmpRequest tool bundled as part of snmp4j, which engineId parameters do I need to set  when sending an INFORM ?
-l , -e , -E ?

I tried setting just the -e flag with 0102030405 on the command line of this tool and still at the receiving end i.e. in the logs of the net-snmp trap collector I see a message of "no match on engineID (80 00 88 .....)"
Basically, the snmptrapd collector is not using 0102030405 for USM engine ID matching purposes. 

If I were to send just a coldStart trap with the SnmpRequest tool bundled in snmp4j distribution, what command line do I need to use ?
My engine ID which I can successfully specify as the authoritativeEngineId via -e flag is 0102030405, when using the snmptrap utility.
I was of the opinion that the same -e flag can be used in SnmpRequest utility as well.

Regards,
Neeraj

--------------------------------------------
On Mon, 19/6/17, Frank Fock <fock at agentpp.com> wrote:

 Subject: Re: [SNMP4J] TCP Socket in SYN_RECV when sending V3 traps
 To: "Neeraj Vaidya" <neeraj.vaidya at yahoo.co.in>
 Cc: snmp4j at agentpp.org
 Date: Monday, 19 June, 2017, 8:31 AM
 
 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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