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Trouble with SNMP traffic sensors



This is going to sound very much like something I posted before, but it is not exactly the same ...

I have a problem with SNMPv2 traffic sensors on interfaces of a VMware server. I create the sensors manualy. When I get the list of interfaces, they are all there and I select the ones I am interested in. But as soon as PRTG starts polling them, it fails, giving "No Such Name (SNMP error #2)".

If I create the sensors with SNMPv1, I do not get the problem. So I suspected that the server was doing SNMPv1 but not SNMPv2c. But, when I try an SNMPv2c walk using MIBtools on my CA Spectrum, I can see all the version 2 interface MIB. The server guys insist they are running SNMPv2c OK, and that there is no IP access-list that would explian the difference in behaviour.

Any suggestions? Thanks.


error-#2 snmp traffic-sensors

Created on May 3, 2013 3:19:47 PM

4 Replies




the host you are trying to monitor is the ESX host itself or a VM running on the ESX host?

Did you already try to scan for available interfaces using our free SNMP tester


Created on May 6, 2013 7:26:42 AM by  Aurelio Lombardi [Paessler Support]

Last change on May 6, 2013 7:26:58 AM by  Aurelio Lombardi [Paessler Support]



Hi, and thanks for looking into this.

It is the ESX host itself that I am trying to monitor. I have another 21 ESX hosts that seem to be behaving correctly, but the server team upgraded this one a couple of weeks ago, and since then I cannot read the SNMPv2 counters.

The strangest thing is that if I set SNMPv2c for the device and try to create SNMP traffic sensors, I can discover the interfaces OK. But after I create sensors on the actiove ones, they all go red ("Show alarm when disconnected") once PRTG starts trying to read the counters. But if I switch to SNMPv1, I can get the available interfaces, and I can read the 32-bit counters OK.

Unfortunately, 32.bit conters are not sufficient for a 1 Gbps interface polled at 60 seconds.

Yet a Spectrum SNMPv2c walk tells me that the 64-bit counters are all present and correct. With the PRTG tester, scanning the available interfaces, it seems to find them OK:

Found standard interfaces: 1:06:00.0: (001) 06:00.0,Connected,1 GBit/s,Ethernet,06:00.0, 64 Bit 2:08:00.0: (002) 08:00.0,Connected,1 GBit/s,Ethernet,08:00.0, 64 Bit etc.

But later it says:

Testing standard interfaces... Test 1:06:00.0 (, in=110772312 out=No such instance (SNMP error # 223) Test 2:08:00.0 (, in=1185681122 out=No such instance (SNMP error # 223) Test 3:26:04.0 (, in=1185407148 out=No such instance (SNMP error # 223) etc.

Best regards Kevin DORRELL

Created on May 6, 2013 8:00:38 AM



OK, I have some more information. Looking very carefully at the SNMPwalk, I see that most of the ifXTable is OK, except that is completely missing. This looks like a bug in the SNMP agent. What do you think? ESXi 5.1 Update 01 Build Number: 1065491

Best regards Kevin DORRELL

Created on May 6, 2013 9:56:32 AM




on our ESXi 5.1 Host we simply used

~ # esxcli system snmp set --communities public ~ # esxcli system snmp set --enable true

to enable snmp and it works with v1 and v2

we can add traffic sensors, SNMP CPU sensor and SNMP Disk Free sensors to it.

our ESX hosts are still on 5.1.0, 914609

I will update one today to check if that makes a difference.

Created on May 6, 2013 1:22:52 PM by  Aurelio Lombardi [Paessler Support]

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