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SNTP sensor reports code PE085



I have dozens of servers and all monitoring NTP with the SNTP sensor. However one SNTP sensor on one server is reporting this error. I have checked the server in question and found NTP to be working fine.

How do I trouble shoot this error?

Server - Ubuntu 12.04 PRTG -

Thanks --Kenny

linux ntp sntp

Created on Apr 15, 2015 3:52:47 PM

4 Replies



The error means that PRTG could not understand the reply from the target server. Could you try doing a wireshark trace of the NTP packets and check if all fields are populated correctly in the packet?
Best regards

Created on Apr 16, 2015 1:01:16 PM by  Konstantin Wolff [Paessler Support]




How does the sensor handle the response flags?

When the leap indicator bits are both high - i.e., unsynchronized, the sensor displays PE085 When the leap indicator bits are low, i.e. normal, the sensor is OK.

In either case, time is still transmitted and the packet looks perfectly fine.

So this doesn't really seem like a case of "PRTG could not understand", rather, it seems like it's setting a generic error condition because the clock is unsynchronized and my switches are, in fact, lying to me by telling me the clock is synchronized when there are syslog messages that correspond perfectly to the time at which the PRTG sensor transitioned to a DOWN state, but I digress - that's HP's fault.

I think it would be worthwhile to implement better support for these flags, so that the sensor can display the appropriate values.

Created on Sep 23, 2016 6:02:06 PM



Hi Jason, Currently the sensor handles the value 3 (Alarm condition (clock not synchronized)) in the Leap Indicator bit as Error as outlined here.
The packet in this case will look perfectly fine but basically the results from it are completely disregarded and said error message is thrown.
All other Leap Indicator bits (values 0,1,2) are handled correctly, though.
We will have a look at the calculation and flag handing but at this point I cannot guarantee if or when this will be implemented.
Best regards

Created on Sep 26, 2016 12:59:50 PM by  Konstantin Wolff [Paessler Support]



You might also encounter PE058 if you are monitoring a VM within Hyper-V if Hyper-V's time synchronisation feature has been enabled. This will prevent an actual NTP-based time synchronization and instead use the host's clock. Either don't use the SNTP sensor in this case, or disable Hyper-V's VM clock synchronisation feature for the VM.

Created on Jan 3, 2023 11:48:39 AM by  Timo Dambach [Paessler Support]

Disclaimer: The information in the Paessler Knowledge Base comes without warranty of any kind. Use at your own risk. Before applying any instructions please exercise proper system administrator housekeeping. You must make sure that a proper backup of all your data is available.