[SNMP4J] SNMP4J V3 Traps with specified Engine ID

[Boussour, Imene (6076618)]

Hello List,

I am trying to send SNMP V3 Traps to a remote server (using a Trap monitor software on windows) from my Java application, I use SNMP4j stack API.
My questions is around the engine ID, on the Trap receiver application we need to create an SNMP V3 account with, username, auth protocol... but also a Context Name.
On the SNMP4j side, there is multiple areas where we can define of set the engineID:
1 - USM usm = new USM(SecurityProtocols.getInstance().addDefaultProtocols(), new OctetString(MPv3.createLocalEngineID()), 0);
2- snmp.getUSM().addUser(mSecurityName, OctetString.fromHexString("80:00:13:70:c0:a8:01:0d"), new UsmUser(mSecurityName, mAuthProtocol, , mPrivProtocol, mPrivPassphrase));
3- UsmUser(mSecurityName, mAuthProtocol, , mPrivProtocol, mPrivPassphrase), OctetString.fromHexString("80:00:13:70:c0:a8:01:0d"));
4- pdu.setContextEngineID(OctetString.fromHexString("80:00:13:70:c0:a8:01:0d"));

For context Name , I only found this:
pdu.setContextName(new OctetString("contextName"));


The SNMP4J createlocalEngineId method creates a random number, Can this work?
My understanding of SNMP trap V3, is that the Engine ID should match on the sender and receiver. So, when we specify a custom engine ID on SNMP4J, which one should we use?

And here is the Code I am using to send Traps:

                     // ltargetAddress represents the host and port we plan to communicate with
                     // in the format: host/port
                     Address ltargetAddress = GenericAddress.parse (mTransportType + ":" + mRemoteAddress + "/" + mRemotePort);

                     TransportMapping<?> transport;
                     if (ltargetAddress instanceof UdpAddress) {
                           transport = new DefaultUdpTransportMapping();
                     } else {
                           transport = new DefaultTcpTransportMapping();
                     }

                     //Create SNMP Session
                     Snmp snmp = new Snmp(transport);

                     USM usm = new USM(SecurityProtocols.getInstance()
                                  .addDefaultProtocols(), new OctetString(
                                  MPv3.createLocalEngineID()), 0);

                     SecurityProtocols.getInstance().addPrivacyProtocol(new PrivAES192());

                     SecurityModels.getInstance().addSecurityModel(usm);

                     //transport.listen();

                     //Setting the security protocols
                     snmp.getUSM().addUser(
                                  mSecurityName,
                                  new UsmUser(mSecurityName, mAuthProtocol,
                                                mAuthPassphrase, mPrivProtocol,
                                                mPrivPassphrase));


                     // Create Target
                     UserTarget target = new UserTarget();
                     target.setAddress(ltargetAddress);
                     target.setRetries(1);
                     target.setTimeout(11500);
                     target.setVersion(SnmpConstants.version3);
                     target.setSecurityLevel(SecurityLevel.AUTH_PRIV);
                     target.setSecurityName(mSecurityName);

                     // Create PDU for V3
                     ScopedPDU pdu = new ScopedPDU();
                     pdu.setType(ScopedPDU.TRAP);

                     // Adding OIDs
                     pdu.add(new VariableBinding(SnmpConstants.sysUpTime,
                    new OctetString(new Date().toString())));

                     pdu.add(new VariableBinding(SnmpConstants.snmpTrapOID,
                                                       SnmpConstants.linkDown));

                     pdu.add(new VariableBinding(new OID(mOID), new OctetString(pMessage)));

                     pdu.add(new VariableBinding(SnmpConstants.snmpTrapAddress,

                     new IpAddress(mRemoteAddress)));

                     //Send the PDU
                     snmp.listen();
                     snmp.send(pdu, target);
                     snmp.close();

Thanks,
Imene