[SNMP4J] Empty SNMP Packets send to Agent

[Daniel Frank]

Hello,

I'm sorry that I didn't provide any further information for the problem.

This is what I captured with Wireshakr for one set-request which successfully set the property
on the network component:

No.     Time           Source                Destination           Protocol Length Info
     41 5.404718000    10.2.1.21             10.2.1.240            SNMP     195    set-request 1.3.6.1.4.1.9.9.513.1.7.4.1.1.12.104.3.3.149.208

Frame 41: 195 bytes on wire (1560 bits), 195 bytes captured (1560 bits) on interface 0
Ethernet II, Src: WistronI_97:0f:b7 (3c:97:0e:97:0f:b7), Dst: CiscoInc_e0:60:05 (e0:ac:f1:e0:60:05)
Internet Protocol Version 4, Src: 10.2.1.21 (10.2.1.21), Dst: 10.2.1.240 (10.2.1.240)
User Datagram Protocol, Src Port: 65210 (65210), Dst Port: 161 (161)
Simple Network Management Protocol
    msgVersion: snmpv3 (3)
    msgGlobalData
        msgID: 1237400771
        msgMaxSize: 65535
        msgFlags: 07
            .... .1.. = Reportable: Set
            .... ..1. = Encrypted: Set
            .... ...1 = Authenticated: Set
        msgSecurityModel: USM (3)
    msgAuthoritativeEngineID: 00003763000060006406a8c0
        0... .... = Engine ID Conformance: RFC1910 (Non-SNMPv3)
        Engine Enterprise ID: Airespace, Inc (formerly 'Black Storm Networks') (14179)
        AgentID Trailer: 0x000060006406a8c0
    msgAuthoritativeEngineBoots: 1
    msgAuthoritativeEngineTime: 1952429
    msgUserName: SecTestUser
    msgAuthenticationParameters: 4739f56e8828a1b8857127d4
        [Authentication: OK]
            [Expert Info (Chat/Checksum): SNMP Authentication OK]
                [SNMP Authentication OK]
                [Severity level: Chat]
                [Group: Checksum]
    msgPrivacyParameters: 53d380fb215c5e78
    msgData: encryptedPDU (1)
        encryptedPDU: 95d0aa3fcf935f4ba649678b9d81fee6912d0b1fe93e8e4c...
            Decrypted ScopedPDU: 303d040c00003763000060006406a8c00400a32b0204164d...
                contextEngineID: 00003763000060006406a8c0
                    0... .... = Engine ID Conformance: RFC1910 (Non-SNMPv3)
                    Engine Enterprise ID: Airespace, Inc (formerly 'Black Storm Networks') (14179)
                    AgentID Trailer: 0x000060006406a8c0
                contextName: 
                data: set-request (3)
                    set-request
                        request-id: 374145296
                        error-status: noError (0)
                        error-index: 0
                        variable-bindings: 1 item
                            1.3.6.1.4.1.9.9.513.1.7.4.1.1.12.104.3.3.149.208: 
                                Object Name: 1.3.6.1.4.1.9.9.513.1.7.4.1.1.12.104.3.3.149.208 (iso.3.6.1.4.1.9.9.513.1.7.4.1.1.12.104.3.3.149.208)
                                Value (Integer32): 2

No.     Time           Source                Destination           Protocol Length Info
     42 5.405533000    10.2.1.240            10.2.1.21             SNMP     194    get-response 1.3.6.1.4.1.9.9.513.1.7.4.1.1.12.104.3.3.149.208

Frame 42: 194 bytes on wire (1552 bits), 194 bytes captured (1552 bits) on interface 0
Ethernet II, Src: CiscoInc_e0:60:00 (e0:ac:f1:e0:60:00), Dst: WistronI_97:0f:b7 (3c:97:0e:97:0f:b7)
Internet Protocol Version 4, Src: 10.2.1.240 (10.2.1.240), Dst: 10.2.1.21 (10.2.1.21)
User Datagram Protocol, Src Port: 161 (161), Dst Port: 65210 (65210)
Simple Network Management Protocol
    msgVersion: snmpv3 (3)
    msgGlobalData
        msgID: 1237400771
        msgMaxSize: 4096
        msgFlags: 03
            .... .0.. = Reportable: Not set
            .... ..1. = Encrypted: Set
            .... ...1 = Authenticated: Set
        msgSecurityModel: USM (3)
    msgAuthoritativeEngineID: 00003763000060006406a8c0
        0... .... = Engine ID Conformance: RFC1910 (Non-SNMPv3)
        Engine Enterprise ID: Airespace, Inc (formerly 'Black Storm Networks') (14179)
        AgentID Trailer: 0x000060006406a8c0
    msgAuthoritativeEngineBoots: 1
    msgAuthoritativeEngineTime: 1952429
    msgUserName: SecTestUser
    msgAuthenticationParameters: 6c42ce550b043adda25bb7cb
        [Authentication: OK]
            [Expert Info (Chat/Checksum): SNMP Authentication OK]
                [SNMP Authentication OK]
                [Severity level: Chat]
                [Group: Checksum]
    msgPrivacyParameters: a022f203000000b8
    msgData: encryptedPDU (1)
        encryptedPDU: dd04f0158d06e1337c7f3a69a56d4c423794a0099c8998c5...
            Decrypted ScopedPDU: 303d040c00003763000060006406a8c00400a22b0204164d...
                contextEngineID: 00003763000060006406a8c0
                    0... .... = Engine ID Conformance: RFC1910 (Non-SNMPv3)
                    Engine Enterprise ID: Airespace, Inc (formerly 'Black Storm Networks') (14179)
                    AgentID Trailer: 0x000060006406a8c0
                contextName: 
                data: get-response (2)
                    get-response

The request is sent like this:
ResponseEvent response = snmp.set(pdu, target);

The ResponseEvent is not empty, but when I try to get the PDU via
response.getResponse() it is null.

And I need to evaluate the response to tell the user, if it was successful or not.

The ID seems to be ok.

Thanks for your help in advance.

Best regards,
Daniel

-----Ursprüngliche Nachricht-----
Von: SNMP4J [mailto:snmp4j-bounces at agentpp.org] Im Auftrag von Jochen Katz
Gesendet: Montag, 14. Dezember 2015 18:59
An: snmp4j at agentpp.org
Betreff: Re: [SNMP4J] Empty SNMP Packets send to Agent

Hello,

> Now I have another problem. I do some set requests and the values are 
> set successfully, but the response parameter of the ResponseEvent is 
> always null.
> 
> What could be the problem there? In Wireshark I can see the response 
> with all necessary informations about the successful action.

without some log information it is difficult to find the cause of this.
Either the response cannot be matched to request (SNMPv3 message id does not match) or the response contains wrong or none SNMPv3 time information or something completely different.

Regards,
  Jochen

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