SNMP Monitoring of ports shows no performance data

Troubleshooting
1

cee 2.3.0p27
Ubuntu 22.04 lts

Hi everybody,

i´m currently stuck at an issue in my checkmk.
We are using checkmk for monitoring of our 36 pfsense-firewalls.
The monitoring is done via SNMPv2.
Since the 26 february we are facing an issue regarding performance data for a few of these firewalls.
Since then, checkmk is not able to provide any information for some ports of these firewalls.
It just shows an empty Perf-O-Meter with the following error message:

Could not compute rates for the following counter(s): in_octets: No time difference, in_ucast: No time difference, in_mcast: No time difference, in_bcast: No time difference, in_disc: No time difference, in_err: No time difference, out_octets: No time difference, out_ucast: No time difference, out_mcast: No time difference, out_bcast: No time difference, out_disc: No time difference, out_err: No time difference
The uptime did not change since the last check cycle. It is likely that no new data was collected.

image
image1160×312 49.4 KB

It seems that this error only occurs on the physical ports of those firewalls but not on any virtual port.
I already checked the log to see if there were changes made in the config of our sites on the specified day, which is not the case.
Also it does not seem to happen at any specific firewall version.
I even tried to delete a firewall and add it as a new host.

If someone can provide help that would be marvellous.

1 Like
2

As a first step, update to the latest patch release and see, if that helps. :v:

1 Like
3

Hi Robin,

thanks for the quick answer.
I did an update to 2.3.0p34 on friday but theres still no data available for the entire weekend.
So it seems that the update has not fixed my issue.

1 Like
4

Update

I finally found the reason for this behaviour.
All firewalls with this issue were added to checkmk on the same date.
And for all of these firewalls the uptime stops at 1year 132 days.
This is also the maximum figure for the TimeTicks in snmp ( 2^32 - 1 = 4,294,967,295 Ticks)

So checkmk is not able to receive any newer information because the timestamp wont change.

Is there any way to ignore this timestamp?

5

Were you able to fix this problem?

6

The fix is a reboot of the firewall.
From the description i would say that this firewall firmware has a faulty SNMP implementation. If a counter reaches it’s maximum it should roll over but not stay at the last value.

1 Like
7

Yes, a reboot would fix this.

But we cannot just simply reboot our datacenter firewall.