[SNMP4J] SNMP code that does not work with TCP

[Frank Fock]

Hello Anmol,

If you read your stack trace, you will see that the NullPointerException
occurs in

       System.out.println("Response is..." + responsePDU.toString());

which means that responsePDU is null. Either your agent does not
support TCP or the timeout is too low. In either case you should change
your code to test responsePDU for null before printing it or simply use

       System.out.println("Response is..." + responsePDU);
 
Best regards,
Frank

Anmol Sinha wrote:

>Hello Frank,
> 
>Attached is the java code written for SNMP using TCP.
>I am using the latest SNMP4J.JAR (v1.5.1).
>The given code works fine for UDP.
> 
>
>import org.snmp4j.*;
>import org.snmp4j.event.ResponseEvent;
>import org.snmp4j.mp.MPv3;
>import org.snmp4j.mp.MessageProcessingModel;
>import org.snmp4j.mp.SnmpConstants;
>import org.snmp4j.security.AuthMD5;
>import org.snmp4j.security.PrivDES;
>import org.snmp4j.security.SecurityLevel;
>import org.snmp4j.security.SecurityModels;
>import org.snmp4j.security.SecurityProtocols;
>import org.snmp4j.security.USM;
>import org.snmp4j.security.UsmUser;
>import org.snmp4j.smi.Address;
>import org.snmp4j.smi.GenericAddress;
>import org.snmp4j.smi.OID;
>import org.snmp4j.smi.OctetString;
>import org.snmp4j.smi.UdpAddress;
>import org.snmp4j.smi.VariableBinding;
>import org.snmp4j.transport.DefaultTcpTransportMapping;
>import org.snmp4j.transport.DefaultUdpTransportMapping;
> 
>public class SNMPV3Test1
>{     
>    public void  RunnableSender()
>    {
>     try
>     {
>        Address targetAddress = GenericAddress.parse("tcp:193.168.1.79/4700");
>        TransportMapping transport = new DefaultTcpTransportMapping();
>        Snmp snmp = new Snmp(transport);
>        MPv3 mpv3 =
>            (MPv3)snmp.getMessageProcessingModel(MessageProcessingModel.MPv3);
>        USM usm = new USM(SecurityProtocols.getInstance(),
>                          new OctetString(MPv3.createLocalEngineID()), 0);
>        SecurityModels.getInstance().addSecurityModel(usm);
>        transport.listen();
>                
>        snmp.getUSM().addUser(new OctetString("MD5DES"),
>              new UsmUser(new OctetString("MD5DES"),
>                          AuthMD5.ID,
>                          new OctetString("MD5DESUserAuthPassword"),
>                          PrivDES.ID,
>                          new OctetString("MD5DESUserPrivPassword")));
>                         
>        UserTarget target = new UserTarget();
>        target.setAddress(targetAddress);
>        target.setRetries(1);
>        target.setTimeout(5000);
>        target.setVersion(SnmpConstants.version3);
>        target.setSecurityLevel(SecurityLevel.AUTH_PRIV);
>        target.setSecurityName(new OctetString("MD5DES"));
>  
>        
>        PDU pdu = new ScopedPDU();
>        pdu.add(new VariableBinding(new OID("1.3.6.1.6.3.16.1.2.1.3.1.6.112.117.98.108.105.99")));
>        pdu.setType(PDU.GET);
>  
>        // send the PDU
>        ResponseEvent response = snmp.send(pdu, target);
>  
>        PDU responsePDU = response.getResponse();
>        System.out.println("Response is..." + responsePDU.toString());
>        
>        Address peerAddress = response.getPeerAddress();
>        System.out.println("Address is..." + peerAddress.toString());
>     }
>     catch(Exception exp){
>      exp.printStackTrace();
>     }
>    }
>  public static void main(String[] args) throws InterruptedException{
>   SNMPV3Test1 snmpRequest = new SNMPV3Test1();
>    snmpRequest.RunnableSender();
>  }
>}
> 
> 
>The stack trace is....
>
>java.lang.NullPointerException
>
>at SNMPV3Test1.RunnableSender(SNMPV3Test1.java:63)
>
>at SNMPV3Test1.main(SNMPV3Test1.java:74)
>
> 
> 
>If I replace the TCP method with UDP i.e.
>        Address targetAddress = GenericAddress.parse("udp:193.168.1.79/4700");
>        TransportMapping transport = new DefaultUdpTransportMapping();
>
>The code works fine and gives the expected result.
>
> 
>Thanks & Regards,
>Anmol
> 
> 
> 
> 
> 
> 
> 
>
>Frank Fock <fock at agentpp.com> wrote:
>Hello Anmol,
>
>Could you please post the stack trace of the NullPointerException you get
>and the SNMP4J version you are using?
>
>Thanks in advance,
>Frank
>
>Anmol Sinha wrote:
>
>  
>
>>Hello All,
>>
>>I have Sucessfully written and tested the SNMP code for UDP protocol for all versions i.e. 1, 2 & 3.
>>I want to have the same code to support TCP protocol also. I just replaced statement...
>>DefaultUdpTransportMapping dutm = new DefaultUdpTransportMapping();
>>with
>>DefaultTcpTransportMapping dutm = new DefaultTcpTransportMapping();
>>
>>But on execution i get Null Pointer Exception. The code works fine for UDP.
>>Can someone help me, so that I know if I have missed out something or some configuration changes.
>>
>>Thanks,
>>Anmol
>>
>>
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>>    
>>
>
>
>		
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>  
>


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