[SNMP4J] Setting Local port in DefaultUdpTransport causes null responses.
Frank Fock
fock at agentpp.com
Wed Mar 2 23:30:00 CET 2011
Hi,
You need to close the transport in order
to be able to bind the port again.
The OS might block a rebind for several
seconds/minutes.
What are you trying to test/show with
the code?
Why do you want to specify a specific
local port? (I do not recommend that
for several reasons)
Best regards,
Frank
On 02.03.2011 23:21, Giuseppe Sarno wrote:
> Hello,
> new to SNMP and to this API.
> I am trying to use code snippet from http://www.snmp4j.org/doc/org/snmp4j/Snmp.html to build a SNMP manager that sends a SET between 2 nodes (SNMP4J 1.11.2).
> I use Java executors to invoke the task that will actually perform the work. I noticed that this works ok if I don't set the LocalPort in the UDP transport.
> I actually would like to fix the port to a specific value so I set it in the transport constructor. Unfortunately after this change the PDU response is always "null".
> Messages are correctly sent and replied back (checked with wireshark). I am not too sure whether there is any threading issue as the transport is bound to a specific port or simply my code is not correct.
>
> Can anybody please let me know if there is any problem with this approach and what the problme could be ?
>
> Thanks.
>
>
> The task will:
>
> 1) Creates DefaultUdpTransportMapping (note I need to set the local port and I to add to set the option "reuse" to true as I was getting bind exception)
>
> DefaultUdpTransportMapping(new UdpAddress(InetAddress.getLocalHost(),localport),true);
>
> 2) Creates community target.
>
> CommunityTarget comtarget = new CommunityTarget();
> comtarget.setCommunity(new OctetString(community));
> comtarget.setVersion(snmpVersion);
> comtarget.setAddress(new UdpAddress(ip + "/" + port));
> comtarget.setRetries(0);
> comtarget.setTimeout(100);
>
> 3) Creates a PDU
>
> PDU pdu = new PDU();
>
> 4) Creates SNMP with the UDP transport (above)
>
> Snmp snmp = new Snmp(this.getUDPTransport());
>
> 5) Sends and wait for the resposne:
>
> ResponseEvent response = snmp.set(pdu, comtarget);
> // Process Agent Response
> if (response != null)
> {
> >> do work<<
> }
>
> Excecutor that wraps the code above:
>
> ExecutorService threadExecutor = Executors.newFixedThreadPool( Data.POOL );
> for ( int i=1;i<=100000;i++)
> {
> RunnableTask t = new RunnableTask(Integer.toString(i));
> threadExecutor.execute(t);
> }
> threadExecutor.shutdown(); // shutdown worker threads
> }
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