IIS Manager has a very nice tool to tell you what features are delegated vs non delegated on the server… To find out go to Start—>Run –> InetMgr
Now you can click on the server node and then select the “Feature Delegation” as shown below:
On clicking on the feature delegation IIS Manager will show you all the features which are delegated..
In most of the “Read/Write” scenarios when you modify your site settings using IISManager they are written into the application’s web.config file… Although certain features are locked down by IIS Manager and they cannot be changed in your application’s web.config file…
These features are marked as “Read Only” and “Not Delegated”… By default following features are Read/Only and Not Delegated
In Win 7 there is work being done to allow changing Error Pages in the web.config file as well, although up until Win 7 that was not possible…
Hope this helps!!