As we have discussed, Traps are like events. This is a way the SNMP agent pushes the information to client. Asynchronously, events can be fired to client from server (agent).<\/p>\n
Example:<\/p>\n
SNMP Trap Receiver:<\/strong><\/p>\n Version 1 Trap Sender:<\/strong><\/p>\n Output:<\/strong><\/p>\n Listening on 127.0.0.1\/162 Version 2 Trap Sender:<\/strong><\/p>\n Output:<\/strong><\/p>\n Listening on 127.0.0.1\/162 Generating TRAP in SNMP using SNMP4j<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"advanced_seo_description":"","jetpack_seo_html_title":"","jetpack_seo_noindex":false,"jetpack_post_was_ever_published":false,"_jetpack_newsletter_access":"","_jetpack_dont_email_post_to_subs":false,"_jetpack_newsletter_tier_id":0,"_jetpack_memberships_contains_paywalled_content":false,"jz_research_post":"","_jetpack_memberships_contains_paid_content":false,"footnotes":""},"categories":[12],"tags":[329,183],"class_list":["post-1582","post","type-post","status-publish","format-standard","hentry","category-snmp","tag-java","tag-snmp4j"],"jetpack_featured_media_url":"","jetpack_sharing_enabled":true,"jetpack-related-posts":[{"id":1571,"url":"https:\/\/www.jitendrazaa.com\/blog\/java\/snmp\/create-snmp-client-in-java-using-snmp4j\/","url_meta":{"origin":1582,"position":0},"title":"Create SNMP Client in JAVA Using 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com.G2.SNMP.Trap.receiver;\n\nimport java.io.IOException;\n\nimport org.snmp4j.CommandResponder;\nimport org.snmp4j.CommandResponderEvent;\nimport org.snmp4j.CommunityTarget;\nimport org.snmp4j.MessageDispatcher;\nimport org.snmp4j.MessageDispatcherImpl;\nimport org.snmp4j.MessageException;\nimport org.snmp4j.PDU;\nimport org.snmp4j.Snmp;\nimport org.snmp4j.mp.MPv1;\nimport org.snmp4j.mp.MPv2c;\nimport org.snmp4j.mp.StateReference;\nimport org.snmp4j.mp.StatusInformation;\nimport org.snmp4j.security.Priv3DES;\nimport org.snmp4j.security.SecurityProtocols;\nimport org.snmp4j.smi.OctetString;\nimport org.snmp4j.smi.TcpAddress;\nimport org.snmp4j.smi.TransportIpAddress;\nimport org.snmp4j.smi.UdpAddress;\nimport org.snmp4j.transport.AbstractTransportMapping;\nimport org.snmp4j.transport.DefaultTcpTransportMapping;\nimport org.snmp4j.transport.DefaultUdpTransportMapping;\nimport org.snmp4j.util.MultiThreadedMessageDispatcher;\nimport org.snmp4j.util.ThreadPool;\n\npublic class TrapReceiver implements CommandResponder {\n\tpublic static void main(String[] args) {\n\t\tTrapReceiver snmp4jTrapReceiver = new TrapReceiver();\n\t\ttry {\n\t\t\tsnmp4jTrapReceiver.listen(new UdpAddress("localhost\/162"));\n\t\t} catch (IOException e) {\n\t\t\te.printStackTrace();\n\t\t}\n\t}\n\n\t\/**\n\t * Trap Listner\n\t *\/\n\tpublic synchronized void listen(TransportIpAddress address)\n\t\t\tthrows IOException {\n\t\tAbstractTransportMapping transport;\n\t\tif (address instanceof TcpAddress) {\n\t\t\ttransport = new DefaultTcpTransportMapping((TcpAddress) address);\n\t\t} else {\n\t\t\ttransport = new DefaultUdpTransportMapping((UdpAddress) address);\n\t\t}\n\n\t\tThreadPool threadPool = ThreadPool.create("DispatcherPool", 10);\n\t\tMessageDispatcher mDispathcher = new MultiThreadedMessageDispatcher(\n\t\t\t\tthreadPool, new MessageDispatcherImpl());\n\n\t\t\/\/ add message processing models\n\t\tmDispathcher.addMessageProcessingModel(new MPv1());\n\t\tmDispathcher.addMessageProcessingModel(new MPv2c());\n\n\t\t\/\/ add all security protocols\n\t\tSecurityProtocols.getInstance().addDefaultProtocols();\n\t\tSecurityProtocols.getInstance().addPrivacyProtocol(new Priv3DES());\n\n\t\t\/\/ Create Target\n\t\tCommunityTarget target = new CommunityTarget();\n\t\ttarget.setCommunity(new OctetString("public"));\n\n\t\tSnmp snmp = new Snmp(mDispathcher, transport);\n\t\tsnmp.addCommandResponder(this);\n\n\t\ttransport.listen();\n\t\tSystem.out.println("Listening on " + address);\n\n\t\ttry {\n\t\t\tthis.wait();\n\t\t} catch (InterruptedException ex) {\n\t\t\tThread.currentThread().interrupt();\n\t\t}\n\t}\n\n\t\/**\n\t * This method will be called whenever a pdu is received on the given port\n\t * specified in the listen() method\n\t *\/\n\tpublic synchronized void processPdu(CommandResponderEvent cmdRespEvent) {\n\t\tSystem.out.println("Received PDU...");\n\t\tPDU pdu = cmdRespEvent.getPDU();\n\t\tif (pdu != null) {\n\t\t\tSystem.out.println("Trap Type = " + pdu.getType());\n\t\t\tSystem.out.println("Variables = " + pdu.getVariableBindings());\n\t\t\t}\n\t\t}\n\t}\n<\/pre>\n\npackage com.G2.SNMP.Trap.Sender;\n\nimport org.snmp4j.CommunityTarget;\nimport org.snmp4j.PDU;\nimport org.snmp4j.PDUv1;\nimport org.snmp4j.Snmp;\nimport org.snmp4j.TransportMapping;\nimport org.snmp4j.mp.SnmpConstants;\nimport org.snmp4j.smi.IpAddress;\nimport org.snmp4j.smi.OID;\nimport org.snmp4j.smi.OctetString;\nimport org.snmp4j.smi.UdpAddress;\nimport org.snmp4j.transport.DefaultUdpTransportMapping;\n\npublic class TrapSenderVersion1 {\n\n\tpublic static final String community = "public";\n\n\t\/\/ Sending Trap for sysLocation of RFC1213\n\tpublic static final String Oid = ".1.3.6.1.2.1.1.8";\n\n\t\/\/IP of Local Host\n\tpublic static final String ipAddress = "127.0.0.1";\n\n\t\/\/Ideally Port 162 should be used to send receive Trap, any other available Port can be used\n\tpublic static final int port = 162;\n\n\tpublic static void main(String[] args) {\n\t\tTrapSenderVersion1 trapV1 = new TrapSenderVersion1();\n\t\ttrapV1.sendTrap_Version1();\n\t}\n\t\/**\n\t * This methods sends the V1 trap to the Localhost in port 162\n\t *\/\n\tpublic void sendTrap_Version1() {\n\t\ttry {\n\t\t\t\/\/ Create Transport Mapping\n\t\t\tTransportMapping transport = new DefaultUdpTransportMapping();\n\t\t\ttransport.listen();\n\n\t\t\t\/\/ Create Target\n\t\t\tCommunityTarget cTarget = new CommunityTarget();\n\t\t\tcTarget.setCommunity(new OctetString(community));\n\t\t\tcTarget.setVersion(SnmpConstants.version1);\n\t\t\tcTarget.setAddress(new UdpAddress(ipAddress + "\/" + port));\n\t\t\tcTarget.setTimeout(5000);\n\t\t\tcTarget.setRetries(2);\n\n\t\t\tPDUv1 pdu = new PDUv1();\n\t\t\tpdu.setType(PDU.V1TRAP);\n\t\t\tpdu.setEnterprise(new OID(Oid));\n\t\t\tpdu.setGenericTrap(PDUv1.ENTERPRISE_SPECIFIC);\n\t\t\tpdu.setSpecificTrap(1);\n\t\t\tpdu.setAgentAddress(new IpAddress(ipAddress));\n\n\t\t\t\/\/ Send the PDU\n\t\t\tSnmp snmp = new Snmp(transport);\n\t\t\tSystem.out.println("Sending V1 Trap... Check Wheather NMS is Listening or not? ");\n\t\t\tsnmp.send(pdu, cTarget);\n\t\t\tsnmp.close();\n\t\t} catch (Exception e) {\n\t\t\te.printStackTrace();\n\t\t}\n\t}\n\n}\n<\/pre>\n
\nReceived PDU…
\nTrap Type = -92
\nVariables = []<\/p><\/blockquote>\n\npackage com.G2.SNMP.Trap.Sender;\n\nimport java.util.Date;\n\nimport org.snmp4j.CommunityTarget;\nimport org.snmp4j.PDU;\nimport org.snmp4j.Snmp;\nimport org.snmp4j.TransportMapping;\nimport org.snmp4j.mp.SnmpConstants;\nimport org.snmp4j.smi.IpAddress;\nimport org.snmp4j.smi.OID;\nimport org.snmp4j.smi.OctetString;\nimport org.snmp4j.smi.UdpAddress;\nimport org.snmp4j.smi.VariableBinding;\nimport org.snmp4j.transport.DefaultUdpTransportMapping;\n\npublic class TrapSenderVersion2 {\n\n\tpublic static final String community = "public";\n\n\t\/\/ Sending Trap for sysLocation of RFC1213\n\tpublic static final String Oid = ".1.3.6.1.2.1.1.8";\n\n\t\/\/IP of Local Host\n\tpublic static final String ipAddress = "127.0.0.1";\n\n\t\/\/Ideally Port 162 should be used to send receive Trap, any other available Port can be used\n\tpublic static final int port = 162;\n\n\tpublic static void main(String[] args) {\n\t\tTrapSenderVersion2 trapV2 = new TrapSenderVersion2();\n\t\ttrapV2.sendTrap_Version2();\n\t}\n\t\/**\n\t * This methods sends the V1 trap to the Localhost in port 162\n\t *\/\n\tpublic void sendTrap_Version2() {\n\t\ttry {\n\t\t\t\/\/ Create Transport Mapping\n\t\t\tTransportMapping transport = new DefaultUdpTransportMapping();\n\t\t\ttransport.listen();\n\n\t\t\t\/\/ Create Target\n\t\t\tCommunityTarget cTarget = new CommunityTarget();\n\t\t\tcTarget.setCommunity(new OctetString(community));\n\t\t\tcTarget.setVersion(SnmpConstants.version2c);\n\t\t\tcTarget.setAddress(new UdpAddress(ipAddress + "\/" + port));\n\t\t\tcTarget.setRetries(2);\n\t\t\tcTarget.setTimeout(5000);\n\n\t\t\t\/\/ Create PDU for V2\n\t\t\tPDU pdu = new PDU();\n\n\t\t\t\/\/ need to specify the system up time\n\t\t\tpdu.add(new VariableBinding(SnmpConstants.sysUpTime,\n\t\t\t\t\tnew OctetString(new Date().toString())));\n\t\t\tpdu.add(new VariableBinding(SnmpConstants.snmpTrapOID, new OID(\n\t\t\t\t\tOid)));\n\t\t\tpdu.add(new VariableBinding(SnmpConstants.snmpTrapAddress,\n\t\t\t\t\tnew IpAddress(ipAddress)));\n\n\t\t\tpdu.add(new VariableBinding(new OID(Oid), new OctetString(\n\t\t\t\t\t"Major")));\n\t\t\tpdu.setType(PDU.NOTIFICATION);\n\n\t\t\t\/\/ Send the PDU\n\t\t\tSnmp snmp = new Snmp(transport);\n\t\t\tSystem.out.println("Sending V2 Trap... Check Wheather NMS is Listening or not? ");\n\t\t\tsnmp.send(pdu, cTarget);\n\t\t\tsnmp.close();\n\t\t} catch (Exception e) {\n\t\t\te.printStackTrace();\n\t\t}\n\t}\n\n}\n<\/pre>\n
\nReceived PDU…
\nTrap Type = -89
\nVariables = [1.3.6.1.2.1.1.3.0 = Wed Feb 16 01:17:02 IST 2011, 1.3.6.1.6.3.1.1.4.1.0 = 1.3.6.1.2.1.1.6, 1.3.6.1.6.3.18.1.3.0 = 127.0.0.1, 1.3.6.1.2.1.1.6 = Major]<\/p><\/blockquote>\n","protected":false},"excerpt":{"rendered":"