[SNMP4J] UnknowHost Exception while sending the snmp trap

Thu Mar 7 01:18:14 CET 2013

Frank:
Could you please answer my follow up questions?

I may attempt test program today my day time.

Thanks,
Parash

On Wed, Mar 6, 2013 at 6:50 PM, Hallur,Parashuram <hallur.p.t at gmail.com>wrote:

> 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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>>>>
>>>>
>>>
>>
>>
>