Create SNMP Client in JAVA Using SNMP4j

Author posted by Jitendra on Posted on under category Categories SNMP and tagged as Tags , with 44 Comments on Create SNMP Client in JAVA Using SNMP4j

Create SNMP Client in JAVA Using SNMP4j

There are lots of open source library for SNMP is available, even java have library for the same,  But in this article I will explain a simple example of using SNMP4j in JAVA to create a simple client which will display the hardware information.

Note : To run this program, SNMP service must be installed. Check this article to know that how to install SNMP in Windows XP.

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Create Simple NMS (Network management station / Client) in JAVA using SNMP4j:

package com.G2.SNMP.client;


import org.snmp4j.CommunityTarget;
import org.snmp4j.PDU;
import org.snmp4j.Snmp;
import org.snmp4j.Target;
import org.snmp4j.TransportMapping;
import org.snmp4j.event.ResponseEvent;
import org.snmp4j.smi.Address;
import org.snmp4j.smi.GenericAddress;
import org.snmp4j.smi.OID;
import org.snmp4j.smi.OctetString;
import org.snmp4j.smi.VariableBinding;
import org.snmp4j.transport.DefaultUdpTransportMapping;

public class SNMPManager {

Snmp snmp = null;
String address = null;

* Constructor
* @param add
public SNMPManager(String add)
address = add;

public static void main(String[] args) throws IOException {
* Port 161 is used for Read and Other operations
* Port 162 is used for the trap generation
SNMPManager client = new SNMPManager("udp:");
* OID - . => SysDec
* OID - . => SysName
* => MIB explorer will be usefull here, as discussed in previous article
String sysDescr = client.getAsString(new OID("."));

* Start the Snmp session. If you forget the listen() method you will not
* get any answers because the communication is asynchronous
* and the listen() method listens for answers.
* @throws IOException
private void start() throws IOException {
TransportMapping transport = new DefaultUdpTransportMapping();
snmp = new Snmp(transport);
// Do not forget this line!

* Method which takes a single OID and returns the response from the agent as a String.
* @param oid
* @return
* @throws IOException
public String getAsString(OID oid) throws IOException {
ResponseEvent event = get(new OID[] { oid });
return event.getResponse().get(0).getVariable().toString();

* This method is capable of handling multiple OIDs
* @param oids
* @return
* @throws IOException
public ResponseEvent get(OID oids[]) throws IOException {
PDU pdu = new PDU();
for (OID oid : oids) {
pdu.add(new VariableBinding(oid));
ResponseEvent event = snmp.send(pdu, getTarget(), null);
if(event != null) {
return event;
throw new RuntimeException("GET timed out");

* This method returns a Target, which contains information about
* where the data should be fetched and how.
* @return
private Target getTarget() {
Address targetAddress = GenericAddress.parse(address);
CommunityTarget target = new CommunityTarget();
target.setCommunity(new OctetString("public"));
return target;



Hardware: x86 Family 6 Model 23 Stepping 10 AT/AT COMPATIBLE – Software: Windows 2000 Version 5.1 (Build 2600 Multiprocessor Free)

Explanation of every method is documented in above program. In Next article, we will write a Java Program to create SNMP Agent.

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  • aslary

    how can i can add the above snmp library to eclipse-IDE.
    I am newbie so please explain it step by step.

    • Suresh V

      @ aslary, select your current project, from the menu choose “Project” and opt for properties in the drop down menu. This opens a Project properties window, select the Libraries tab and click “Add external JARs” button.

      • Hari


        Above code i have to run in my machine (ubuntuOS).following exception is comming any one help me plz iam new from this. Permission denied
        at Method)
        at org.snmp4j.transport.DefaultUdpTransportMapping.(
        at com.aurus.SnmpClient.start(
        at com.aurus.SnmpClient.(
        at com.aurus.SnmpClient.main(

        • Hari

          sorry ,above is another example code below code is this code pls help me any one..

          Exception in thread “main” org.snmp4j.MessageException: Operation not permitted
          at org.snmp4j.MessageDispatcherImpl.sendPdu(
          at org.snmp4j.Snmp.sendMessage(
          at org.snmp4j.Snmp.send(
          at org.snmp4j.Snmp.send(
          at SNMPManager.get(
          at SNMPManager.getAsString(
          at SNMPManager.main(
          Caused by: Operation not permitted
          at Method)
          at org.snmp4j.transport.DefaultUdpTransportMapping.sendMessage(
          at org.snmp4j.transport.DefaultUdpTransportMapping.sendMessage(
          at org.snmp4j.MessageDispatcherImpl.sendMessage(
          at org.snmp4j.MessageDispatcherImpl.sendPdu(
          … 6 more

  • aslary

    i know now how to get add an external jar file
    but i get an error ->

    Exception in thread “main” java.lang.NullPointerException
    at SNMPManager.getAsString(
    at SNMPManager.main(

    69: return event.getResponse().get(0).getVariable().toString();


  • Hi aslary,
    In eclipse, right click on project, select Build path option and then select import jars.


  • the OID, which you are passing is correct ? Please take the help of MIB explorer which is explained in previous article.

    Jitendra Zaa

  • aslary

    hi zaa,
    first thank you for quit response.
    I am using win7-> could this be a problem?

    best regards

  • cliff

    I am trying to iterate through a variable list of items but am not sure how to implement this, like a get next. I can iterate through my ManagedObjects that I have created with a specific OID but I want to query a group of items (slot numbers) where the base OID is the same and I want to have the query return baseOID.1, baseOID.2,…,baseOID.n

    How can I implement this in SNMP4j – any suggestions?

    • Hi Cliff,
      You can write your own logic. Create a string which have fixed OID and then every time concatenate number and use line no 45,46 and 47 in loop. Its totally depend on your environment. Please elaborate your need if it does not fulfill answer to your query.

      Jitendra Zaa

  • RogerJames

    Thanks for the wonderful article. Could you please let us know the things that are required for running this program successfully…like setting params,installing variables,mibs etc.

  • rajshekar

    Thanks for this article dude. before this had tried and tried unsuccessfully. final works. 🙂

  • hi aslary,

    i too had a similar error , i solved it like this:

    in the line:


    actually while setting community i had given the community name as demopublic. but here it was public. so i modified the line as follows:

    target.setCommunity(new OctetString(“demopublic”));

  • rajshekar

    hey can i get similar program for snmpwalk. this program which you have given is for snmp get.

  • Hi RajShekhar,
    Currently i dont have the program for “snmpwalk”, if i will work or get time then definetly post here. If you will be able to resolve then please share with eceryone so that they can also get benefit.

    Jitendra Zaa

  • Akira

    Thank you guys this code save me.

  • bizowiso

    Awesome post

  • Daniel Estrázulas

    great !! This api is hard to learn, do you have any idea to how change this example for snmp v3 ?

     I’m trying to make a simple GET example using test agent but it always return the same OID ( maybe its a default mib at original test package example )

    What is more strange is that no matter which ones parameters for usm i choose on client… the agent always return the same OID with an incrementing value.

  • Hi. I have a question for you. If I would like to make a java program that will bind every 1 second a variable to a MIB oid that I’ve created (ex: form interfaces i’ve created ifATR and ifOWD) how can I do it. I would like this program just to bind the variable and every time i send a snmp request(using NETSNMP) to respond with that variable.

  • Johan

    Hi there, your snmp4j blog series looks dangerously close to this,, the code examples you are using is the same as that example and even the comments in the code is the same. However, there is no reference to the original article anywhere which I think would be in place.

  • thank you very much

  • Alejandro


    When I tried run this code, I had the same problem that had “aslary”, but when I change the IP address from to a different one (a server IP address) it works.

    Thank you for the example.

  • slash

    when i try to run this code its giving null pointer exception …I guess it may be due to timeout ..any help

  • Ash852006

    I want to run this code on a remote client I changed to when I run the program it gives me :

    Exception in thread “main” java.lang.NullPointerException
        at SNMPManager.getAsString(
        at SNMPManager.main(

    • moonw

      Hi folks, I had the same issue, and I have solved it checking that smtp service is enabled (seems that the error message cause is related with an exception that is not evaluated when the service is not enabled). Then just check that your service is enabled and well configured.

  • AMHiz

    how to install SNMP service on window 7 ?

  • tuanhiep1232

    After sending Get/GetNext request to devices, I closed snmp connection using “snmp.close();”. But when i used TCPView tool to check connections, I found that snmp connection still exist. How to really close snmp connection.?
    Thanks and sorry for my English!

  • Guest1

    When i run this code it shows an error message of package org.snmp4j does not exist. Why is it?

    • This is because you dont have required jar file in your environment.

      • Guest1

        Thanks a lot.

  • Ahmed Ayedi

    When i run this code it shows an error message:

    Exception in thread “main” java.lang.NullPointerException

    at SNMPManager.getAsString(

    at SNMPManager.main(

    can you help me please

    • Overlight

      I also have the same error

  • sog

    hello, I hope you can give me your opinion….
    This example could be used for a Network Monitoring System, i hope your answer, and thank you very much…

  • Mew

    Thanks for the code.
    I wondering if I want to get the ip address that all connected to the router. Can I do that?

  • Nupur Bora

    Hello, i m working on a project of NMS using SNMP protocol. I will develop a android(java based) application, by which i will manage networks devices like routers,switches etc. So can you help me to this coding part of java. I will very thankful to you.

  • Yuvraj

    HI Jitendra,
    Could you plz guide how we can load/read/compile our own mibs. i mean how to proceed with our own mibs

  • palavesamuthu

    HI Jitendra,

    The above program work well, thanks for this.
    Now I want to list all the devices details which are connected in my network, How can I do this??

  • karthik

    Hello Jitendra,
    Thanks for the example and it has been very helpful in understanding the snmp4j framework. But i wanted to ask you if this would work for an ipv6 address? if so,then what is the format for the ipv6 address scheme.?
    i tried “udp:[xxxx:xxxx:xxxx:xxxx:xxxx:xxxx:xxxx:xxxx]/161” but that doesn’t seem to be working. Can you shed some light on this?. Thanks in advance.

  • Surendra Kumar

    how to copy and pate this code without line number .

  • Simla

    Hi Jitendra,
    I am currently working on SNMP monitoring and for now i’m working with localhost

    I’m trying to get CPU and memory usage with SNMP. I have a Java code which takes the oid and runs the “get” command. I can reach the values with MIB-II. However when i import HOST-RESOURCES-MIB in the code i can’t get CPU information it returns Null. But some oids work properly in HOST-RESOURCES-MIB.

    For example:

    hrSystemUpTime(. gives me the value 3:51:15.07
    hrProcessorLoad(. gives me the value Null

    What is the problem?

  • Curtis Newton

    errors : client start is privare and snmpmanager not defined