# What is IIS modules as the root cause? **URL:** \ **Category:** Open Q&A\ **Tags:** services-classic, iis\ **Created:** [April 30, 2019, 10:15am UTC](https://community.dynatrace.com/t/what-is-iis-modules-as-the-root-cause/20506 "2019-04-30T10:15:51Z")\ **Posts on this page:** 10\ **Page:** 1
**Author:** ![dparkar](https://avatars.discourse-cdn.com/v4/letter/d/838e76/32.png) [@dparkar](https://community.dynatrace.com/u/dparkar)\ **Post date:** [April 30, 2019, 10:15am UTC](https://community.dynatrace.com/t/what-is-iis-modules-as-the-root-cause/20506/1 "2019-04-30T10:15:51Z")
Trying to find the root cause of a response degradation. DynaTrace shows that top findings as IIS Modules. Time consumed by IIS modules is equal to response time of the degraded response. Further clicking on IIS modules there is a breakdown which says ‘General’ (100%) ---
**Author:** ![skrystosik](https://dub1.discourse-cdn.com/dynatrace/user_avatar/community.dynatrace.com/skrystosik/32/21133_2.png) [@skrystosik](https://community.dynatrace.com/u/skrystosik)\ **Post date:** [April 30, 2019, 10:27am UTC](https://community.dynatrace.com/t/what-is-iis-modules-as-the-root-cause/20506/2 "2019-04-30T10:27:55Z")
Did you turned on on host (edit settings) beta support for IIS modules? Than you will see list of those modules with response time contribution. In General IIS is webServer, it uses modules to handle session, transactions routing etc. Sometime those modules has issues. Sebastian ---
**Author:** ![dparkar](https://avatars.discourse-cdn.com/v4/letter/d/838e76/32.png) [@dparkar](https://community.dynatrace.com/u/dparkar)\ **Post date:** [April 30, 2019, 10:29am UTC](https://community.dynatrace.com/t/what-is-iis-modules-as-the-root-cause/20506/3 "2019-04-30T10:29:52Z")
Yes that is turned on. ---
**Author:** ![dparkar](https://avatars.discourse-cdn.com/v4/letter/d/838e76/32.png) [@dparkar](https://community.dynatrace.com/u/dparkar)\ **Post date:** [April 30, 2019, 10:33am UTC](https://community.dynatrace.com/t/what-is-iis-modules-as-the-root-cause/20506/4 "2019-04-30T10:33:24Z")
There is a long list of modules under IIS modules on the view response time hotspots page. Out of which it says ‘General’ is contributing 100% to the response degradation. ---
**Author:** ![skrystosik](https://dub1.discourse-cdn.com/dynatrace/user_avatar/community.dynatrace.com/skrystosik/32/21133_2.png) [@skrystosik](https://community.dynatrace.com/u/skrystosik)\ **Post date:** [April 30, 2019, 10:50am UTC](https://community.dynatrace.com/t/what-is-iis-modules-as-the-root-cause/20506/5 "2019-04-30T10:50:56Z")
To analyse it you can check perfview to record session or debugdiag. Both are tools from microsoft. As well you can start performance monitor and check amount of requests on iis, if some of them are waiting. Maybe resources of this IIS are exhausted. Configuration is default or custom? IIS is hard to analyse, such cases needs experts from IIS. DT will not show you more. Sebastian ---
**Author:** ![dparkar](https://avatars.discourse-cdn.com/v4/letter/d/838e76/32.png) [@dparkar](https://community.dynatrace.com/u/dparkar)\ **Post date:** [April 30, 2019, 12:32pm UTC](https://community.dynatrace.com/t/what-is-iis-modules-as-the-root-cause/20506/6 "2019-04-30T12:32:52Z")
Thanks 🙂 ---
**Author:** ![Julius\_Loman](https://dub1.discourse-cdn.com/dynatrace/user_avatar/community.dynatrace.com/julius_loman/32/51_2.png) [@Julius\_Loman](https://community.dynatrace.com/u/Julius_Loman)\ **Post date:** [July 16, 2019, 1:26pm UTC](https://community.dynatrace.com/t/what-is-iis-modules-as-the-root-cause/20506/7 "2019-07-16T13:26:53Z")
From my experience, a high “General” IIS module usage means the client is consuming response slowly. (Client typically has slow network connection). Thus it is not a problem of the application or IIS. ---
**Author:** ![skrystosik](https://dub1.discourse-cdn.com/dynatrace/user_avatar/community.dynatrace.com/skrystosik/32/21133_2.png) [@skrystosik](https://community.dynatrace.com/u/skrystosik)\ **Post date:** [July 16, 2019, 7:53pm UTC](https://community.dynatrace.com/t/what-is-iis-modules-as-the-root-cause/20506/8 "2019-07-16T19:53:23Z")
Can you say something more about it? I’ve got situations like this with couple of minutes spent on general iis module, this was during loadtests where internet connection was just fine. I’m curious about correlation here. Are you suggesting that for example iis is serving 1mb payload which is downloaded by client for some time? From my experience with iis there aren’t only one explenation for the same symptoms. I rather prefer java applications or at least .net core for analysis 🙂 Sebastian ---
**Author:** ![Julius\_Loman](https://dub1.discourse-cdn.com/dynatrace/user_avatar/community.dynatrace.com/julius_loman/32/51_2.png) [@Julius\_Loman](https://community.dynatrace.com/u/Julius_Loman)\ **Post date:** [July 17, 2019, 7:00am UTC](https://community.dynatrace.com/t/what-is-iis-modules-as-the-root-cause/20506/9 "2019-07-17T07:00:43Z")
I agree, it’s difficult to debug and this is not the only single explanation. However, I’ve done some testing and this slow network (large http responses with the combination of slow or laggy connection lead to this outcome). ---
**Author:** ![skrystosik](https://dub1.discourse-cdn.com/dynatrace/user_avatar/community.dynatrace.com/skrystosik/32/21133_2.png) [@skrystosik](https://community.dynatrace.com/u/skrystosik)\ **Post date:** [July 17, 2019, 7:06am UTC](https://community.dynatrace.com/t/what-is-iis-modules-as-the-root-cause/20506/10 "2019-07-17T07:06:52Z")
Good to know for the future 🙂 I’ll check this clue when I will have such issue next time