Is there a way to force the http sensor to use the IP address of the associated device instead of resolving the name specified in URL?

I need to monitor an external and an internal web server in a split DNS setup which use the same url and I cannot find a way to do it.

I also tried the multiline port sensor, in order to send the http request manually, but apparently it does not support multiline strings to be sent, so I cannot do it this way either.

I guess I can write a custom sensor in eg Powershell, but I would like to avoid dependencies on executables etc

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Wouldn't it be possible in this situation to monitor the server through the external and internal IP's with different sensors and accomplish this? Or am I misunderstanding the issue?


Sep, 2014 - Permalink

Maybe I miss something, but the http sensor does not connect to the IP defined on the device, but to the IP resolved by the url. So I don't know how to specify the two different IPs, and the server responds to the specific application url only.

eg. This web application can be accessed as https://my.site.example/ It is reachable on public IP 192.0.2.10 and on private IP 192.168.0.10 When I configure the sensor, the sensor will always try to connect to the IP that my.site.example resolves to. Since my prtg installation is on the internal net, it always tries to reach 192.168.0.10 (the sensor's associated device IP is not used).

If I try to access the application with https://192.0.2.10/, the application is not responding because it is configured to respond to "my.site.example" only and unfortunately I cannot change that

Hope this clear things up.


Sep, 2014 - Permalink

In this case, if the site is only available on the 192.168.0.10 IP for the PRTG server itself, I would set up one sensor on the local probe to monitor that IP.

Once you have that set up, you can then set up a remote probe with the same sensor to monitor from an outside internet connection where the 192.0.2.10 is available and that way get stats on the server through both IP addresses.

You will have to have 2 separate sensors to be able to do this and will have to set them up on two different probes that can reach the two different IPs respectively.


Sep, 2014 - Permalink

Well, 192.0.2.10 is accessible for the PRTG server, the DNS resolving is the problem.

I think I will either add a remote probe with a customized hosts file or write a small script to do the job


Sep, 2014 - Permalink