Can anyone give a clear explanation of the difference between using clientCredentialType=Windows and =Ntlm in a server-side Web.config when hosting a WCF service?
I have a SOAP 1.1 (basicHttpBinding) service for interop with existing clients. It uses ASP.NET roles so needs clients to be authenticated.
When I am using the VS2005 (Cassini) server to host the service, I have to specify ClientCredentialType=Ntlm as above, and check the Ntlm authentication box in the project properties in VS2005. ClientCredentialType=Windows doesn't work - clients get a 401 Unauthorized error.
However when I'm running under IIS, it's the other way around: ClientCredentialType=Windows works, and ClientCredentialType=Ntlm fails.
Can anyone explain this, and preferably suggest a way I can have the same web.config file to run the service in Cassini and IIS?
Update
I have .NET 3.5 SP1 on my dev machine, which is XP SP2 running in a domain. Cassini therefore runs under a domain account, and IIS 5.1 under a local account.
I wonder if it could be related to the breaking change in .NET 3.5SP1 described in these articles.
http://www.aspnetpro.com/newsletterarticle/2008/12/asp200812ab_l/asp200812ab_l.asp http://msmvps.com/blogs/alvin/archive/2008/11/14/net-3-5-sp1-breaking-change-to-wcf.aspx http://connect.microsoft.com/VisualStudio/feedback/ViewFeedback.aspx?FeedbackID=354236
The situation sounds similar as clientCredentialType=Windows fails when the server is running under a domain account (which is my situation with Cassini - running as my normal domain user account), and works when running under a local account (which is my situation with IIS).
The problem is that the suggested fixes require changes to a WCF client configuration file - but in my case I'm using SOAP 1.1 (basicHttpBinding) with non-WCF clients.