Silverlight client identity not always passed to server?
I have a Silverlight client that has some problems talking to the server it originates from via a WCF `basicHttpBinding`. The service configuration is as follows:

    <system.serviceModel>
      <bindings>
        <basicHttpBinding>
          <binding name="silverlightBinding">
            <security mode="TransportCredentialOnly">
              <transport clientCredentialType="Windows" />
            </security>
          </binding>
        </basicHttpBinding>
      </bindings>
      <services>
        <service name="MyServices.ImportService">
          <endpoint address="" binding="basicHttpBinding"
                    contract="MyServices.IImportService"
                    bindingConfiguration="silverlightBinding" />
        </service>
      </services>
      <serviceHostingEnvironment aspNetCompatibilityEnabled="true"/>
    </system.serviceModel>

The server is an IIS6 web server that is configured to use integrated authentication. The application pool identity is a domain account.

Now some calls from the Silverlight client to the web server include the client identity (the domain user that accesses the client) and some do not! I have included a part of the IIS log to show this:

    2009-12-09 14:10:00 W3SVC1490499214 10.0.0.113 GET /ClientBin/MySLApp.xap - 80 BROWNIE\TestUser 10.0.0.216 Mozilla/4.0+(compatible;+MSIE+7.0;+Windows+NT+5.1) 304 0 0
    2009-12-09 14:12:33 W3SVC1490499214 10.0.0.113 POST /Services/ImportService.svc - 80 - 10.0.0.216 Mozilla/4.0+(compatible;+MSIE+7.0;+Windows+NT+5.1) 401 2 2148074254
    2009-12-09 14:12:33 W3SVC1490499214 10.0.0.113 POST /Services/ImportService.svc - 80 - 10.0.0.216 Mozilla/4.0+(compatible;+MSIE+7.0;+Windows+NT+5.1) 401 2 2148074254
    2009-12-09 14:12:33 W3SVC1490499214 10.0.0.113 POST /Services/ImportService.svc - 80 - 10.0.0.216 Mozilla/4.0+(compatible;+MSIE+7.0;+Windows+NT+5.1) 401 1 0
    2009-12-09 14:12:33 W3SVC1490499214 10.0.0.113 POST /Services/ImportService.svc - 80 BROWNIE\TestUser 10.0.0.216 Mozilla/4.0+(compatible;+MSIE+7.0;+Windows+NT+5.1) 200 0 0
    2009-12-09 14:12:33 W3SVC1490499214 10.0.0.113 POST /Services/ImportService.svc - 80 - 10.0.0.216 Mozilla/4.0+(compatible;+MSIE+7.0;+Windows+NT+5.1) 401 1 0
    2009-12-09 14:12:34 W3SVC1490499214 10.0.0.113 POST /Services/ImportService.svc - 80 BROWNIE\TestUser 10.0.0.216 Mozilla/4.0+(compatible;+MSIE+7.0;+Windows+NT+5.1) 200 0 0
    2009-12-09 14:12:34 W3SVC1490499214 10.0.0.113 POST /Services/ImportService.svc - 80 - 10.0.0.216 Mozilla/4.0+(compatible;+MSIE+7.0;+Windows+NT+5.1) 401 1 0
    2009-12-09 14:12:34 W3SVC1490499214 10.0.0.113 POST /Services/ImportService.svc - 80 BROWNIE\TestUser 10.0.0.216 Mozilla/4.0+(compatible;+MSIE+7.0;+Windows+NT+5.1) 200 0 0

If you scroll a little to the right, you see that for some requests an identity is known (`BROWNIE\TestUser`). For most requests, however, this is not the case. It's as if the client 'randomly' chooses when to send an identity along.

Has anyone ever seen this behavior and found a solution?
Silverlight client identity not always passed to server?
===

I have a Silverlight client that has some problems talking to the server it originates from via a WCF `basicHttpBinding`. The service configuration is as follows:

    <system.serviceModel>
      <bindings>
        <basicHttpBinding>
          <binding name="silverlightBinding">
            <security mode="TransportCredentialOnly">
              <transport clientCredentialType="Windows" />
            </security>
          </binding>
        </basicHttpBinding>
      </bindings>
      <services>
        <service name="MyServices.ImportService">
          <endpoint address="" binding="basicHttpBinding"
                    contract="MyServices.IImportService"
                    bindingConfiguration="silverlightBinding" />
        </service>
      </services>
      <serviceHostingEnvironment aspNetCompatibilityEnabled="true"/>
    </system.serviceModel>

The server is an IIS6 web server that is configured to use integrated authentication. The application pool identity is a domain account.

Now some calls from the Silverlight client to the web server include the client identity (the domain user that accesses the client) and some do not! I have included a part of the IIS log to show this:

    2009-12-09 14:10:00 W3SVC1490499214 10.0.0.113 GET /ClientBin/MySLApp.xap - 80 BROWNIE\TestUser 10.0.0.216 Mozilla/4.0+(compatible;+MSIE+7.0;+Windows+NT+5.1) 304 0 0
    2009-12-09 14:12:33 W3SVC1490499214 10.0.0.113 POST /Services/ImportService.svc - 80 - 10.0.0.216 Mozilla/4.0+(compatible;+MSIE+7.0;+Windows+NT+5.1) 401 2 2148074254
    2009-12-09 14:12:33 W3SVC1490499214 10.0.0.113 POST /Services/ImportService.svc - 80 - 10.0.0.216 Mozilla/4.0+(compatible;+MSIE+7.0;+Windows+NT+5.1) 401 2 2148074254
    2009-12-09 14:12:33 W3SVC1490499214 10.0.0.113 POST /Services/ImportService.svc - 80 - 10.0.0.216 Mozilla/4.0+(compatible;+MSIE+7.0;+Windows+NT+5.1) 401 1 0
    2009-12-09 14:12:33 W3SVC1490499214 10.0.0.113 POST /Services/ImportService.svc - 80 BROWNIE\TestUser 10.0.0.216 Mozilla/4.0+(compatible;+MSIE+7.0;+Windows+NT+5.1) 200 0 0
    2009-12-09 14:12:33 W3SVC1490499214 10.0.0.113 POST /Services/ImportService.svc - 80 - 10.0.0.216 Mozilla/4.0+(compatible;+MSIE+7.0;+Windows+NT+5.1) 401 1 0
    2009-12-09 14:12:34 W3SVC1490499214 10.0.0.113 POST /Services/ImportService.svc - 80 BROWNIE\TestUser 10.0.0.216 Mozilla/4.0+(compatible;+MSIE+7.0;+Windows+NT+5.1) 200 0 0
    2009-12-09 14:12:34 W3SVC1490499214 10.0.0.113 POST /Services/ImportService.svc - 80 - 10.0.0.216 Mozilla/4.0+(compatible;+MSIE+7.0;+Windows+NT+5.1) 401 1 0
    2009-12-09 14:12:34 W3SVC1490499214 10.0.0.113 POST /Services/ImportService.svc - 80 BROWNIE\TestUser 10.0.0.216 Mozilla/4.0+(compatible;+MSIE+7.0;+Windows+NT+5.1) 200 0 0

If you scroll a little to the right, you see that for some requests an identity is known (`BROWNIE\TestUser`). For most requests, however, this is not the case. It's as if the client 'randomly' chooses when to send an identity along.

Has anyone ever seen this behavior and found a solution?