This article applies to PRTG Network Monitor 8.2 or later
Behavior of Ping and Port Sensor Changed
With PRTG version 8.2, we changed the way Ping and Port sensors measure response times.
The Old Method
In previous versions, PRTG always added the time needed to resolve a DNS name to an IP address to the response time measured for actual Ping and Port requests:
Result value = DNS resolution time + response time
For Ping requests, for example, this resulted in different values reported by PRTG, when compared to the results shown by the Windows Ping command, when a DNS name was pinged. However, measurements for host names containing an IP address were not affected by this issue, as DNS resolution is not required in these cases.
What's New As Of Version 8.2?
Due to frequent user requests, we now changed the default behavior of Ping and Port sensors so they now merely show the response time without the DNS resolution:
Result value = response time
In your monitoring graphs, you might therefore notice a huge drop in response times for these sensor types (depending on the performance of your DNS servers).
Can I Still Use the Old Method?
If the changed values are a problem for you, and you want to restore the old measurement method after upgrading to PRTG 8.2, there is a registry setting that allows to enable the old method.
For detailed instructions, please see: How can I change the default behavior of Ping and Port sensors regarding DNS resolution measurement?
Add comment