SNMP – receiving traps without community

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Hi,

We have an appliance that sends out traps without including a community string.
Is it possible to process these in dataminer ?

With the generic trap receiver protocol one has to provide a community string (can not be left balnk).
Is there a way to make traps without community string still arrive in the element ?

Thanks in advance.

Miguel Obregon [SLC] [DevOps Catalyst] Answered question 31st January 2025

1 Answer

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Hi Hans,

I made a small test and the traps are processed by the connector 'Generic Trap Receiver', regardless of the community string. Below the element settings:

Using Net-SNMP tools, I sent the following trap:

snmptrap -v 1 -c nopublic 10.11.12.13 '1.3.6.1.4.35416' '10.11.12.13 6 2 '55' 1.3.6.1.4.35416.2.2.2.3.1.4.70.28 i 10

The community string is 'nopublic'. As you can see in the screenshot below, the trap is processed by the element:

I also tested using SNMPv2 traps and I can confirm that the traps are also processed.

Hope it helps.

Update:

Test with sending a SNMP Trap without community string:

Miguel Obregon [SLC] [DevOps Catalyst] Posted new comment 4th February 2025
hans sanders [DevOps Advocate] commented

Thanks a lot for the test but I am afraid our use-case is a little different still. We have NO community string in the trap.
So I wonder if you can simulate that condition…
Miguel Obregon [SLC] [DevOps Catalyst] commented

Hi Hans,
I was able to simulate a SNMP trap without community string. See updated answer with an screenshot of the Wireshark capture.
Hope it helps.
Vincent Dessy commented

So we are using the 1.0.1.22 of the Generic Trap receiver on ramses.

When i send this trap i receive well the trap in the element:
/usr/bin/snmptrap -v 2c -c "ramses" 195.238.16.72 '' .1.3.6.1.4.1.20006.1.6.0 .1.3.6.1.4.1.20006.1.6.2 s "HOSTNAME" .1.3.6.1.4.1.20006.1.6.3 s "HOSTDESC" .1.3.6.1.4.1.20006.1.6.4 s "HOST" .1.3.6.1.4.1.20006.1.6.5 s "1" .1.3.6.1.4.1.20006.1.6.6 s "HOSTOUTPUT" .1.3.6.1.4.1.20006.1.6.7 s "HOSTNOTIFICATIONID"

When i send the exact same without anything in the community filed i confirm that we don't receive anything.
/usr/bin/snmptrap -v 2c -c "" 195.238.16.72 '' .1.3.6.1.4.1.20006.1.6.0 .1.3.6.1.4.1.20006.1.6.2 s "HOSTNAME" .1.3.6.1.4.1.20006.1.6.3 s "HOSTDESC" .1.3.6.1.4.1.20006.1.6.4 s "HOST" .1.3.6.1.4.1.20006.1.6.5 s "1" .1.3.6.1.4.1.20006.1.6.6 s "HOSTOUTPUT" .1.3.6.1.4.1.20006.1.6.7 s "HOSTNOTIFICATIONID"

Can be a due to the driver version ?
Miguel Obregon [SLC] [DevOps Catalyst] commented

Hi Vincent,
I was using a different driver version than yours.
Can you try testing version 1.0.2.2?
I performed a small test on my end (using the sample trap that you provided) and I was able to see the trap being processed by the element.
Vincent Dessy commented

Same driver version has been installed and the result is the same using the same trap/command.
Maybe the trap is blocked before reaching the driver on this system.
Also executed a wireshark trace at same time on the dma server and on this level i can see the two trap arriving. (pcap file available on request.
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