We want to check some web sites availability from a special server (named "A" for instance) which has access to internet via a proxy server (named "B" for instance). so in PRTG server (named "C" for instance)we added a http sensor for server "A" and in "Proxy settings for http sensors" entered Name & port of server"B" (there is no need for Credentials).after all HTTP sensor is "Down" with this Error message: HTTP/1.1 502 Proxy Error ( Forefront TMG denied the specified Uniform Resource Locator (URL). )

beside this our proxy server(B) is TMG & all needed rules are added.

The Rule which makes Sensor Status "Down" From: Server"A" To: All networks Users: All users Protocols: HTTP & HTTPs

PRTG Server(C) has no access to internet via the proxy but when it is allowed to connect to internet via the proxy server, sensor status changes to "UP".

The Rule which makes Sensor Status "UP": From: PRTG Server(C) To: All networks Users: All users Protocols: HTTP & HTTPs

it seems that it checks that URL from PRTG Server(C) through Proxy. how can we check that website from Server A not PRTG?

Article Comments

Hi,
In your described case, you might have a look into remote probes. So in general a HTTP Sensor checks the URL but only from the machine PRTG resp. the remote probe is installed. So the sensor behaviour is absolutely normal as the server (C) where PRTG is installed has no internet access.
Now when you install a remote probe on server A, all sensors under the remote probe will scan the target from this server.
Best regards


Apr, 2016 - Permalink