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DHCP-Sensor also returns reservations; that defeats the object



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Hello team,

I configured a DHCP-sensor on the probe device (= my workstation, with fixed IP to be able to detect when we run out of IP-Address Leases; which happens regularly.

This sensor checks with a regular expression if de DHCP-server returns a valid IP-address; like 192.168.1.x. This regular expression is checked and is correct.

But this sensor is always green, even if the DHCP-server has run out of IP-addresses, because it does always returns

And this is because is part of the reservations. But that is obviously not what I want to check.

Question: is there a solution for this on the shelf, or do I need to write a custom sensor for this?

Thank you in advance,

Jos Bijleveld CTO Enigma Flowers B.V. Netherlands

dhcp ip-address leases prtg reservations

Created on Dec 14, 2016 12:16:16 PM by  Jos Bijleveld (0) 1

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Dear Jos,

Thank you very much for your knowledge base post.

As far as I understand your request, you like monitor the scope release of your DHCP. On the other hand, the DHCP sensor monitors the lease time, given by the DHCP to the device the sensor is installed to. The described sensor's behavior is not false as it applies only for that device.

Unfortunately, PRTG does not offer a proper out of the box sensor, therefore you will need to write a custom sensor for that. Please refer to this knowledge base thread (11433) on how to set up a monitoring for the DHCP scope release. Please pay attention on this reply (221198) if you have Windows Server 2012 R2.


Created on Dec 15, 2016 2:49:30 PM by  Sebastian Kniege [Paessler Support]

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