What is this?

This knowledgebase contains questions and answers about PRTG Network Monitor and network monitoring in general.

Learn more

PRTG Network Monitor

Intuitive to Use. Easy to manage.
More than 500,000 users rely on Paessler PRTG every day. Find out how you can reduce cost, increase QoS and ease planning, as well.

Free Download

Top Tags

View all Tags

snmp trap handling when no trap is received (Keep Last Sensor state)



Hello there,

I am using the PRTG Network Monitor and trying to receive snmp V2 traps. When it comes to receiving traps I am receiving them without problem.

My company has the following specific demands which must be met:

1) Keep Last Sensor state even though that there is no traps being received. Explanation: I have a software which sends sporadic traps. It may not send any traps for long time ex: a month. I want to keep the sensor's state same as the last received trap.(Currently sensor automatically changes its state to 'UP' when there is no traps received.)

2) Receive trap content via e-mail. I have a sensor whose Error filter is configured as ex: 'not bindings[,ok]'. The sensor goes to down state when it receives anything other then 'ok' message. The problem is that when I receive emails from PRTG it only shows number of error traps received. I need to know which particular trap content forced the sensor to down state.


last-sensor-state snmp snmp-trap traps-are-not-send

Created on Apr 7, 2014 8:45:05 AM

2 Replies



That's what I was waiting for..

As a software developer, I need this ability to inform PRTG about the final state of my software. As an examle, think that I have a web site that's not so busy. I am making an HTTP request to any other web service each time a user visits my page. I send an snmp trap to PRTG, each time my web site tries to make that HTTP request. I send Success if my web site can reach the web service, and Fail otherwise. As I said before, my site is not busy, time between each visit may vary (between 1 second to 10 minutes). So the last time a visitor visited my site, my web service call was Fail and I got an alarm. And then no visitiors came to my site for 10 minutes. My sensor must still be in DOWN state. But in PRTG it goes UP after a while.

I don't understand the logic behind this. This is really useless. I would be glad if this feature (actually for me, it is not a feature, it is a bug of PRTG) is added to PRTG.

Thank you

Created on Apr 9, 2014 7:36:17 AM



Since this sensor is still in beta, we are considering this request for a change in how the sensor functions. I cannot say when this will be changed or if it will be changed. If we decide to move forward with this, I will post more information here.

As to being able to send the last SNMP trap from the sensor in a notification, this should be possible very soon with a new placeholder that should be coming out in the next main version release. Thanks for the feedback, we always appreciate it!

Created on Apr 9, 2014 3:04:28 PM by  Greg Campion [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.