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

Monitor SMTP Virtual Server




We have an SMTP Virtual Server setup in IIS 6.0 Manager running on our Windows server that acts as our email relay to our hosted Exchange for printers and other scan to email devices.

I have tried the sensor Windows IIS 6.0 SMTP Sent to monitor, but it has failed in adding. My purpose is to be notified if the service stops. Is this the correct sensor? If so how do I set it up, if not what sensor should I be using?

Thanks, Tim

iis prtg smtp

Created on Mar 16, 2017 7:44:55 PM

5 Replies



Hi there,

Please use the "WMI Service" sensor instead to monitor the current state of the SMTP-Service.

Best regards.

Created on Mar 20, 2017 10:01:11 AM by  Dariusz Gorka [Paessler Support]




That only seems to monitor the SMTP service. I am successfully monitoring that service already. What I would like to monitor is if the SMTP Virtual Server state (start/stop) in IIS 6.0. If I manually stop the SMTP Virtual Server in IIS 6.0, the SMTP Service continues to run thus not alerting me if the SMTP Virtual Server has stopped.

Thanks, Tim

Created on Mar 20, 2017 8:03:51 PM



Also interested to know if this can be achieved too

Created on Sep 11, 2018 12:35:37 PM



Hi Cosmos,

The best approach probably is to make sure SMTP is available on e.g. port 25. The SMTP sensor (default PRTG) might be more sufficient for this.

Another good idea would be to monitor the directories on the IIS itself.

A word of advice out of personal experience with the IIS SMTP engine - it is not actually very powerful nor robust - it has its quirks. If you want something cheap, actually free, look at this alternative service for SMTP that gives you a lot more options, works more stable and is easier to administrate as well: https://www.hmailserver.com/

It is a pretty famous SMTP open source project that really does a good job - have used it a lot for internal SMTP relay servers with great success and eliminating a lot of the issues and challenges with IIS. I monitor the h-mail service, the SMTP port/connection and the SMTP queue directory for to many files and to old files (e.g. 1 hour and above) to see if anything got stuck and or stressing the system.


Florian Rossmark


Created on Sep 11, 2018 2:04:14 PM



Hi Tim.

Did you find a way to monitor the stop/start status of an IIS SMTP Virtual Server using PRTG?

I got it to work using the standard SMTP (Tags: smtpsensor+mailsensor) sensor.

What confused me when I was setting it up was that the Scan Now didn't refresh. Setting the scan interval to 30 seconds during testing/setup made things easier.

Regards, Nigel

Created on Feb 5, 2020 11:41:53 PM

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.