I was troubleshooting a problem with WCF where the updates to a remote database were failing. The reason for the failure was found pretty quickly to be delegation.
For general impersonation questions in regards to WCF, there is lots of great information found here.
For my situation, the problem was that the ASP.NET application that was calling the WCF service was impersonating and I couldn’t enable delegation in my environment. So the connection to SQL failed. There are a number of ways to solve this problem, but some have more problems then others.
Fix #1 The easiest way is the add a User ID and Password to the web.config file. But then you have to worry about updating that if the password expires and also the security of having the password in the config file.
Note: You can add the password to the registry ...
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