[SNMP4J] V2 Trap Packet Fragmentation

[Frank Fock]

Hi,

A NullPointerException at that location can be caused
only by a NULL request ID. How you managed to
be NULL - I don't know.
Normally, SNMP4J takes care to set it. So you must have
done something special.

A SNMP packet fragementation does not exists on UDP
level in the way you described it (two packets with their
own header).

Best regards,
Frank

Am 17.04.2012 00:12, schrieb Amol Rao:
> ...any thoughts? anyone?
>
> On Mon, Apr 16, 2012 at 4:09 PM, Amol Rao<xamolrao at gmail.com>  wrote:
>> I see the following exception when trap is being sent out. Any pointers?
>>
>>
>> java.lang.NullPointerException
>>         at org.snmp4j.PDU.getBERPayloadLengthPDU(PDU.java:499)
>>         at org.snmp4j.PDU.getBERLength(PDU.java:436)
>>         at org.snmp4j.mp.MPv2c.prepareOutgoingMessage(MPv2c.java:118)
>>         at org.snmp4j.MessageDispatcherImpl.sendPdu(MessageDispatcherImpl.java:444)
>>         at org.snmp4j.Snmp.sendMessage(Snmp.java:1078)
>>         at org.snmp4j.Snmp.send(Snmp.java:878)
>>         at org.snmp4j.Snmp.send(Snmp.java:871)
>>         at org.snmp4j.Snmp.send(Snmp.java:836)
>>         at org.snmp4j.Snmp.notify(Snmp.java:780)
>>
>>
>> Cheers,
>> Amol
>>
>> On Mon, Apr 16, 2012 at 1:05 PM, Amol Rao<xamolrao at gmail.com>  wrote:
>>> Hi All:
>>>   Just wanted to reach out and see if anyone encountered this situation.
>>>
>>> I am sending out an SNMP trap (~1K size) from an agent system. When
>>> manager receives the trap, its observe that its divided into multiple
>>> traps and each trap carries one variable binding - which leads to
>>> conclusion that the packets are getting fragmented at the SNMP level,
>>> I wonder why this happens.
>>>
>>> I did wireshark and realized that there is no UDP level fragmentation.
>>>
>>> Both source (trap generation) and Destination (trap receiver) uses
>>> snmp4j-1.11.jar but since on the receiving side, I have logic that
>>> expects the trap to come in as one UDP packets, the whole thing breaks
>>> apart. Moreover, I observed that its happening on only one system, the
>>> same code works on another identical system.
>>>
>>> Any pointers as to why this could be happening and what is the way around?
>>>
>>> I am pretty sure that we are not crossing UDP packet limit, not that
>>> it would matter at SNMP layer.
>>>
>>> Thanks.
>>>
>>> Cheers,
>>> Amol
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