we recently saw some odd behaviour with IIS. The website became unavailable so I logged on to the server on whcih IIS is insalled.
I encountered a screen informing me that a host of IIS role services had been removed. To our knowledge, anyone who has access to the server did not manually instigate this. It is as though it instigated itself, bizarrely.
The website and IIS were running as normal yesterday morning when I checked. But by the evening time soemthing had happened.
When I checked the event logs for anything related to IIS in the timeframe mentioned I came across these messages:
System Error Logs:
"The Application Host Helper Service encountered an error while reading the data for SID mapping. Please ensure that the application pool name data is correct in the configuration file. To resolve this issue, please recommit the changes or restart this service. The data field contains the error number."
"The Application Host Helper Service encountered an error trying to process the configuration data for config history. The feature will be isabled. To resolve this issue, please confirm that the configuration file is correct, has correct attribute values for config history and recommit the changes. The feature will be enabled again if the configuration is correct. The data field contains the error number."
Application Error Logs:
Event 2280, IIS-W3SVC-WP
"The Module DLL C:\Windows\System32\inetsrv\iisetw.dll failed to load. The data is the error."
I did some research on these errors and found the following KB article:
Can someone please explain it in more layman's terms? There seems to be some corruption which caused the IIS roles to eb removed. Does the KB article relate to what we've seen?