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ISAPI Native Extension - breaking purepaths


Hi all,

I'm at a customer site and trying to setup AppMon agents on IIS7.x. The agents have loaded successfully however I have incomplete purepaths between IIS and the application server. Initially I suspected that it was due to a native CGI element but they inform me they've switched to using an ISAPI extension.

So far I haven't been able to find much detail around supported monitoring for applications using native ISAPI extensions and was hoping someone had experience with this that they can share.

Will it be the same as with the native CGI and the use of the ADK be required? Is there another way to complete the purepaths? Any advice would be appreciated.


Dynatrace Leader
Dynatrace Leader

April, One possible cause of this behavior is that the header we inject into the request going back to the .NET tier is being stripped by a Load balancer or firewall (or something) between the IIS tier and .NET tier. I have seen some customers allow only explicit request parameters and header values. Check to see if they have a white-list-only policy in place.

To my awareness the ISAPI module is accepting the call doing some level of processing and generating calls out the other side. As it's a 1 call to many the tagging won't necessarily return a good result?

Dynatrace Pro
Dynatrace Pro

Hi April,

if it's a native ISAPI extension, that means it's an extension written in native code (as opposed to managed code like Java and .NET). To instrument native code with AppMon, you'll always need the ADK. We cannot follow a transaction into native code without instrumenting it first with the ADK.

Please let us know if I understood you correctly.

I had guessed that that would be the case. I was wondering if anyone had a creative "go around" for it, but I know that's a bit of a shot in the dark. Thanks anyway for your help in replying.