[SNMP4J] UnknowHost Exception while sending the snmp trap

Wed Mar 6 14:20:26 CET 2013

Frank:
Thanks again for your response. I'm sorry if I was unclear.

Let me add little more elaboration.

1. With snmp4j-1.0.jar : Application is bind to IPv6 socket address.
In this case trying to send the trap fails with the
java.nio.BufferOverFlowException is thrown.

2. With snmp4j-2.0.jar : Application is bind to all machine IP addresses.
Here the application is running/listening on dual stack mode.
In this case I get the  "UnknownHostException" while parsing the target
address.

3. With snmp4j-2.0.jar : Application is bind to only IPv6 socket address.
The application is running/listening on IPv6 only address
 In this case also, I get the "UnknownHostException" while parsing the
target address

A question about the address parsing
This piece of code works for the application running on Ipv6 only, which
tries to send the trap?
 Address targetAddress =
GenericAddress.parse("udp:<HostName>:<TrapReceiverPort>/162");

I will make an attempt to write test program and let you know how it goes.

Thanks,
Parash

On Wed, Mar 6, 2013 at 6:35 PM, Frank Fock <frank.fock at t-online.de> wrote:

>  Hi Parash,
>
> The scenario with the three cases you described below does not make any
> sense to me.
> With "the application is bind to an address" you probably mean, the SNMP4J
> listen
> address. If so, this could not relate to the exception of case 1.
> Regarding case 2 and 3, seems to be simply a wrong target address and is
> unrelated to
> the local address SNMP4J is bound too.
>
> I think you should investigate this further and write a small - only
> SNMP4J based application
> that reproduces the error. I do not think that we can get any progress
> otherwise.
>
> Best regards,
> Frank
>
> Am 06.03.2013 09:27, schrieb Hallur,Parashuram:
>
> Reposting the complete thread with currect subject
> -------------------------------------------------------------------------
>
> Hi Frank:
>
> As I mentioned in my original email, the host is not getting recognized,
> it throws the "UnknownHostException" at the
> InetAddress.getByName("HostName"). The reason is the host name will be sent
> by snmp4j as "localhost:1622" to this underneath api, ideally it should not
> be sent with the trap receiver port. I tried this both for IPv4 and IPv6
> address application, in both cases I see the same issue with snmp4j-2.0.jar.
>
> My application is configurable to bind to particular address, it can be
> configured to bind to single socket address or multiple socket addresses.
>
> Following are the cases I tried
> 1. With snmp4j-1.0.jar : Application is bind to IPv6 socket address, the
> java.nio.BufferOverFlowException is thrown.
> 2. With snmp4j-2.0.jar : Application is bind to all machine IP addresses.
> "UnknownHostException" while parsing the target address
> 3. With snmp4j-2.0.jar : Application is bind to only IPv6 socket address.
> "UnknownHostException" while parsing the target address
>
> The code used to parse the address is -
>
>  Address targetAddress =
> GenericAddress.parse("udp:<HostName>:<TrapReceiverPort>/162");
>
> Am I missing something here? Appreciate your help very much. Please let me
> know if you need more details.
>
> Thanks,
> Parash
>
> --------
>
> OK, that'a no problem. So then why do you get an exception?
>
> Am 06.03.2013 01:15, schrieb Hallur,Parashuram:
>
> --------
>
> Thank you so much for the response Frank.
>
> What do you exactly mean by "trap is bound to IPv6 address"?
>
> This means, the application which is running on IPv6 address is trying to
> send a notification to the trap receiver running on a dual stack IP ( both
> Ipv4 & IPv6 )mode machine.
>
> Thanks,
> Parash
>
> ----------
>
> Hi Parash,
>
> What do you exactly mean by "trap is bound to IPv6 address"?
>
> (If you tried to set the agentAddress field in a trap/notification with a
> IPv6 address
> you will fail, as SNMP supports IPv4 addresses only for this field.
>
> Best regards,
> Frank
>
> Am 06.03.2013 01:05, schrieb Hallur,Parashuram:
>
>
>
> On Wed, Mar 6, 2013 at 5:39 AM, Hallur,Parashuram <hallur.p.t at gmail.com>wrote:
>
>>   Frank or any body else on the forum:
>>
>>  Would you please help me with pointers on how to fix this issue? What
>> needs to be done to be able to send the traps from IPv6 application?
>>  Thanks for any pointers.
>>
>>  Parash
>>
>>
>> On Tue, Mar 5, 2013 at 7:24 AM, Hallur,Parashuram <hallur.p.t at gmail.com>wrote:
>>
>>>   Thanks Frank for the response. Yes the application which is trying to
>>> send the trap is bound to IPv6 address, would you please help me with how
>>> to fix this issue?
>>>
>>>  Thanks,
>>>  Parash
>>>
>>>
>>>  On Mon, Mar 4, 2013 at 11:44 PM, Frank Fock <fock at agentpp.com> wrote:
>>>
>>>> Hi,
>>>>
>>>> I think you are trying to sent an IPv6 address as IpAddress BER encoded
>>>> on the wire. This is not possible, because the SNMP standard defines
>>>> IpAddress as IPv4 address and nothing else.
>>>> If this worked with 1.0 then this was an error in 1.0.
>>>>
>>>> Best regards,
>>>> Frank
>>>>
>>>> Am 04.03.2013 12:24, schrieb Hallur,Parashuram:
>>>>
>>>>>  Hi,
>>>>>
>>>>> I'm using the following code to create the target address.
>>>>>
>>>>> Address targetAddress =
>>>>> GenericAddress.parse("udp:<HostName>:<TrapReceiverPort>/162");
>>>>>
>>>>> This goes through fine when I use the snmp4j1.0.jar. However, this
>>>>> particular version seems does not support the IPv6 addresses. For IPv6
>>>>> requests it throws the java.nio.BufferOverFlowException.
>>>>> java.nio.BufferOverflowException
>>>>>      at java.nio.Buffer.nextPutIndex(Unknown Source)
>>>>>      at java.nio.HeapByteBuffer.put(Unknown Source)
>>>>>      at org.snmp4j.asn1.BEROutputStream.write(BEROutputStream.java:65)
>>>>>      at org.snmp4j.asn1.BER.encodeOID(BER.java:437)
>>>>>      at org.snmp4j.smi.OID.encodeBER(OID.java:205)
>>>>>      at
>>>>> org.snmp4j.smi.VariableBinding.encodeBER(VariableBinding.java:176)
>>>>>      at org.snmp4j.PDUv1.encodeBER(PDUv1.java:207)
>>>>>      at org.snmp4j.mp.MPv1.prepareOutgoingMessage(MPv1.java:108)
>>>>>      at
>>>>>
>>>>> org.snmp4j.MessageDispatcherImpl.sendPdu(MessageDispatcherImpl.java:376)
>>>>>      at org.snmp4j.Snmp.sendMessage(Snmp.java:900)
>>>>>      at org.snmp4j.Snmp.send(Snmp.java:779)
>>>>>      at org.snmp4j.Snmp.send(Snmp.java:771)
>>>>>
>>>>> To fix the above issue, I picked up the latest jars snmp4j2.1.0.jar,
>>>>> snmp4j1.11.3.jar, and snmp4j1.10.jar. All of these throw the unknown
>>>>> host
>>>>> exception. What I notice is that snm4j sends hostname as
>>>>> "hostname:trapreceiverport" to underneath java api to resolve the
>>>>> address,
>>>>> hence the issue unknownhostexception. The same code works with 1.0
>>>>> version
>>>>> of jar. Are there any difference from now and then? Any help is very
>>>>> much
>>>>> appreciated.
>>>>>
>>>>> Thanks,
>>>>> Parash
>>>>>  _______________________________________________
>>>>> SNMP4J mailing list
>>>>> SNMP4J at agentpp.org
>>>>> http://lists.agentpp.org/mailman/listinfo/snmp4j
>>>>>
>>>>
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>>>
>>>
>>
>
>