Hi Kuldeep,
Thank you.
Unfortunately, I didnot capture packets, but there was engineID missing on
SNMP manager during the test. I fixed that and noticed no snmpinforms
then. So checked at snmp-agent side and noticed that snmptrap is stuck.
Does 'snmptrap' not timeout if there is no engineID in response from
SNMP-manager?
*System details:*
net-snmp : 5.7.1
Kernel : 4.1.22-ltsi
machine : arm
OS : linux
Thank you,
Pushpa.T
On Mon, Jun 19, 2023 at 3:54 PM Kuldeep Patidar <kuldeepatida...@gmail.com>
wrote:
> Hello pushpa ..
>
> Thank you for providing the additional information. From the given
> details, it seems that the issue is occurring within the `main()` function
> of the `snmptrap.c` file.
>
> Based on the provided local variables, it appears that the SNMP session is
> configured correctly, including the SNMP version, community string, and
> security parameters. The session has the correct peername set to
> "192.168.18.69," indicating that the destination IP is reachable.
>
> Since the manager IP being unreachable results in a timeout, it is
> possible that there is a network connectivity issue or a problem with the
> SNMP server configuration. However, since you have confirmed that the IP is
> reachable, we can explore other potential causes.
>
> Here are a few suggestions to further investigate the issue:
>
> 1. Verify the response from the SNMP server: Check the SNMP server logs or
> enable debugging on the server side to see if it is receiving the SNMP
> inform request and generating a response. This can help determine if the
> issue lies with the server's handling of the inform requests.
>
> 2. Capture network traffic: Use network monitoring tools (e.g., Wireshark)
> to capture the network traffic between the device running the `snmptrap`
> command and the SNMP server. Analyze the captured packets to ensure that
> the inform request is being sent correctly and that the server is
> responding.
>
> 3. Check for firewall or security restrictions: Ensure that there are no
> firewall rules or security restrictions on either the device running the
> `snmptrap` command or the SNMP server that might be blocking or interfering
> with the SNMP inform packets.
>
> 4. Monitor system resources: Monitor the system resources (CPU, memory,
> disk) on the device running the `snmptrap` command to ensure that it is not
> overwhelmed or experiencing resource constraints that could cause the
> command to hang.
>
> 5. Test with a different SNMP manager: Try sending the SNMP inform to a
> different SNMP manager or tool to see if the issue persists. This can help
> determine if the problem is specific to the SNMP server or if it occurs
> with other managers as well.
>
> 6. Review SNMP library or command versions: Check if there are any known
> issues or bugs related to the SNMP library or the `snmptrap` command
> version you are using. Consider updating to the latest version or trying an
> alternative SNMP library or command implementation.
>
> If none of the above steps resolve the issue, it might be necessary to
> engage the support channels of the SNMP library or the SNMP server vendor
> for further assistance. They can provide more specific guidance and help
> troubleshoot the problem in-depth.
>
> Remember to provide them with the relevant details, such as the SNMP
> library version, operating system, and any error messages or log entries
> associated with the issue.
>
> Thanks
> Kukdeep Paridar
>
> On Mon, 19 Jun 2023, 3:36 pm Pushpa Thimmaiah, <pushpa.thimma...@gmail.com>
> wrote:
>
>> Hi Kuldeep,
>>
>> Thanks a lot for quick response. I did check them, it was working fine
>> and turned into this state at some point time.
>> GDB shows all input args from snmptrap is correct. IP is reachable.
>> I have noticed when manager IP unreachable then it would time out with
>> error:snmpInform: Timeout.
>>
>>
>> ----------------------------------------------------------------------------------------------------------------------------------------------
>> (gdb) frame 3
>> #3 0x00011e00 in main (argc=19, argv=0x0) at snmptrap.c:377 <-----
>> snmp_synch_response() called in this function
>> (gdb) info locals
>> session = {version = 3, retries = 1, timeout = 2000000, flags = 256,
>> subsession = 0x0, next = 0x0, peername = 0x7ed46f05 "192.168.18.69",
>> remote_port = 0, localname = 0x0, local_port = 0, authenticator = 0x0,
>> callback = 0x12658 <snmp_input>, callback_magic = 0x0, s_errno = 0,
>> s_snmp_errno = 0, sessid = 0, community = 0x7ed4672c "public",
>> community_len = 6, rcvMsgMaxSize = 1472, sndMsgMaxSize = 0,
>> isAuthoritative = 0 '\000', contextEngineID = 0x0, contextEngineIDLen =
>> 0, engineBoots = 0, engineTime = 0, contextName = 0x0,
>> contextNameLen = 0, securityEngineID = 0x0, securityEngineIDLen = 0,
>> securityName
>> = 0x29588 "v3", securityNameLen = 2,
>> securityAuthProto = 0x76f34384 <usmHMACMD5AuthProtocol>,
>> securityAuthProtoLen = 10,
>> securityAuthKey = "\274\363\267\031\034\toI\\\331\376\070th\234\345",
>> '\000' <repeats 15 times>, securityAuthKeyLen = 16,
>> securityAuthLocalKey = 0x0, securityAuthLocalKeyLen = 0,
>> securityPrivProto = 0x0, securityPrivProtoLen = 0,
>> securityPrivKey = '\000' <repeats 31 times>, securityPrivKeyLen = 0,
>> securityPrivLocalKey = 0x0, securityPrivLocalKeyLen = 0,
>> securityModel = -1, securityLevel = 2, paramName = 0x0, securityInfo =
>> 0x0, transport_configuration = 0x0, myvoid = 0x0}
>> ss = 0x2310c
>> pdu = 0x2c3e8
>> response = 0x7ed465c0
>> pdu_in_addr_t = <optimized out>
>>
>> On Mon, Jun 19, 2023 at 3:16 PM Kuldeep Patidar <
>> kuldeepatida...@gmail.com> wrote:
>>
>>> Hello ..
>>>
>>> From the provided information, it appears that the `snmptrap` command is
>>> getting stuck in the `snmp_synch_response_cb()` function in the
>>> `snmp_client.c` file. The `state->waiting` flag is set to 1, indicating
>>> that it is waiting for a response.
>>>
>>> To troubleshoot this issue, you can follow these steps:
>>>
>>> 1. Check the SNMP configuration: Ensure that the SNMP configuration on
>>> the device is correct, including the SNMP version, community string, and
>>> authentication settings.
>>>
>>> 2. Verify SNMP server availability: Confirm that the SNMP server is
>>> running and reachable from the device where you are executing the
>>> `snmptrap` command. You can use tools like `snmpwalk` or `snmpget` to check
>>> the SNMP connectivity and retrieve SNMP data from the server.
>>>
>>> 3. Confirm SNMPv3 settings: Since you mentioned using SNMPv3 informs,
>>> verify that the SNMPv3 settings, such as security parameters (username,
>>> authentication protocol, privacy protocol) and context name, are correctly
>>> configured on both the sending and receiving ends.
>>>
>>> 4. Check network connectivity: Ensure that there are no network
>>> connectivity issues between the device and the SNMP server. Verify that the
>>> required ports (typically UDP 161 and 162) are open and accessible.
>>>
>>> 5. Review SNMP timeout and retries: Although you mentioned that the
>>> timeout is set to 2 seconds with 2 retries, it's worth confirming if these
>>> settings are appropriate for your environment. You may consider increasing
>>> the timeout value or adjusting the number of retries to see if it affects
>>> the behavior.
>>>
>>> 6. Debug SNMP agent/server: Enable SNMP debugging or logging on the
>>> receiving SNMP server to gather more information about the incoming
>>> `snmptrap` requests. This can help identify any issues on the server side.
>>>
>>> 7. Update SNMP libraries: If you're using third-party SNMP libraries,
>>> make sure they are up to date. There might be known issues or bug fixes in
>>> newer versions that could resolve the problem.
>>>
>>> 8. Consult vendor documentation or support: If the issue persists, it
>>> may be beneficial to consult the documentation or reach out to the vendor's
>>> support team for assistance. They can provide specific troubleshooting
>>> steps or insights related to their SNMP implementation.
>>>
>>> It's important to note that without additional context or access to the
>>> system, it can be challenging to pinpoint the exact cause of the issue.
>>> Therefore, the above suggestions should help you investigate and resolve
>>> the problem.
>>>
>>> Thanks
>>> Kuldeep patidar
>>>
>>>
>>>
>>> On Mon, 19 Jun 2023, 3:13 pm Pushpa Thimmaiah, <
>>> pushpa.thimma...@gmail.com> wrote:
>>>
>>>>
>>>> Hi Folks,
>>>>
>>>> I am using 'snmptrap -Ci ' to send snmpv3 informs . Noticed scenario
>>>> on one device where snmptrap command stuck and gdb shows that flow stuck
>>>> in snmp_synch_response_cb() . File snmp_client.c, flag state->waiting
>>>> set to 1.
>>>> Kindly guide .
>>>> According to my knowledge, snmpinform will timeout after given period.
>>>> Here timeout is 2 seconds and retry 2.
>>>>
>>>> -------------------------------------------------------------------------------------------------------------------------------------------------------------------------
>>>> bt
>>>> #0 0x76e2e850 in select () at ../sysdeps/unix/syscall-template.S:84
>>>> #1 0x76eddb68 in snmp_synch_response_cb (ss=0x2c288, ss@entry=0x2310c,
>>>> pdu=pdu@entry=0x2c3e8, response=0x7ebd5558,
>>>> response@entry=0x7ebd5550, pcb=<optimized out>) at
>>>> snmp_client.c:1060
>>>> #2 0x76eddc40 in snmp_synch_response (ss=ss@entry=0x2310c,
>>>> pdu=pdu@entry=0x2c3e8, response=response@entry=0x7ebd5550) at
>>>> snmp_client.c:1108
>>>> (gdb) frame 1
>>>> #1 0x76eddb68 in snmp_synch_response_cb (ss=0x2c288, ss@entry=0x2310c,
>>>> pdu=pdu@entry=0x2c3e8, response=0x7ebd5558,
>>>> response@entry=0x7ebd5550, pcb=<optimized out>) at
>>>> snmp_client.c:1060
>>>> 1060 in snmp_client.c
>>>> (gdb) info locals
>>>> lstate = {waiting = 1, status = 1, reqid = 82488738, pdu = 0x0}
>>>> state = 0x7ebd5450
>>>> cbsav = 0x0
>>>> cbmagsav = 0x1
>>>> numfds = 5
>>>> count = <optimized out>
>>>> fdset = {fds_bits = {16, 0 <repeats 31 times>}}
>>>> timeout = {tv_sec = 0, tv_usec = 0}
>>>> tvp = 0x0
>>>> block = 1
>>>> (gdb) frame 2
>>>> #2 0x76eddc40 in snmp_synch_response (ss=ss@entry=0x2310c,
>>>> pdu=pdu@entry=0x2c3e8, response=response@entry=0x7ebd5550) at
>>>> snmp_client.c:1108
>>>> 1108 snmp_client.c: No such file or directory.
>>>> (gdb) info locals
>>>> No locals.
>>>> (gdb)
>>>> (gdb) frame 0
>>>> #0 0x76e2e850 in select () at ../sysdeps/unix/syscall-template.S:84
>>>> 84 T_PSEUDO (SYSCALL_SYMBOL, SYSCALL_NAME, SYSCALL_NARGS)
>>>> (gdb) info locals
>>>> No locals.
>>>> (gdb)
>>>>
>>>> ------------------------------------------------------------------------------------------------------
>>>>
>>>> Thanks,
>>>> Pushpa.T
>>>> _______________________________________________
>>>> Net-snmp-coders mailing list
>>>> Net-snmp-coders@lists.sourceforge.net
>>>> https://lists.sourceforge.net/lists/listinfo/net-snmp-coders
>>>>
>>>
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