To send a broadcast SNMP message to a target, simply
- use a broadcast address as target
- use SNMP v1, v2c, or v3 with
noAuthNoPriv security level (broadcast with authentication does not work obviously) - use the asynchronous response processing model of SNMP4J
For example:
Setup a Snmp instance and let it listen to responses
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TransportMapping transport = new DefaultUdpTransportMapping();
Session snmp = new Snmp(transport);
USM usm = new USM(SecurityProtocols.getInstance(),
new OctetString(MPv3.createLocalEngineID()), 0);
SecurityModels.getInstance().addSecurityModel(usm);
snmp.listen();
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Create a broadcast target
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Address targetAddress = GenericAddress.parse("udp:255.255.255.255/161");
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- SNMP v1
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CommunityTarget target = new CommunityTarget();
target.setCommunity(new OctetString("public"));
target.setAddress(targetAddress);
target.setRetries(1);
target.setTimeout(5000);
target.setVersion(SnmpConstants.version1);
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- SNMP v2c
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CommunityTarget target = new CommunityTarget();
target.setCommunity(new OctetString("public"));
target.setAddress(targetAddress);
target.setRetries(1);
target.setTimeout(5000);
target.setVersion(SnmpConstants.version2c);
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- SNMPv3
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UserTarget target = new UserTarget();
target.setAddress(targetAddress);
target.setRetries(1);
target.setTimeout(5000);
target.setVersion(SnmpConstants.version3);
target.setSecurityLevel(SecurityLevel.NOAUTH_NOPRIV);
target.setSecurityName(new OctetString("unsecUser"));
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Create the PDU
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PDU pdu = new PDU();
pdu.add(new VariableBinding(new OID(new int[] {1,3,6,1,2,1,1,1})));
pdu.add(new VariableBinding(new OID(new int[] {1,3,6,1,2,1,1,2})));
pdu.setType(PDU.GETNEXT);
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Send the message asynchronously
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class MyResponseListener implements ResponseListener {
boolean finished = false;
public void onResponse(ResponseEvent event) {
System.out.println("Received response PDU is: "+event.getResponse());
if (event.getResponse() == null) {
finished = true;
listener.notify();
}
}
public boolean isFinished() {
return finished;
}
};
MyResponseListener listener = new MyResponseListener() {
snmp.sendPDU(pdu, target, null, listener);
try {
while (!listener.isFinished()) {
listener.wait(target.getTimeout()*2);
}
} catch (InterruptedException iex) {
System.out.println("Request cancelled: "+iex.getMessage());
}
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