I am having some problems with the combination of Network Load Balance, SharePoint and Kerberos.SharePoint is configured on 2 computers as a farm and SqlServer is located on another computer.The SharePoint apppool is running as a domain user trusted for delegation and I set SPN for the SharePoint servers.Now I have set up a NLB for the two SharePoint servers. The two computers are combined to a virtual ip address from the Load Balancer which I assigned with a host header name and I set SPN settings to this one, too.This seems to work, however the server is accessing sharepoint files with the apppool user, which has no rights on sharepoint ofcourse. (I have a wcf service on the SharePoint computers with webclient.downloadfile(loadbalanceurl) code to download a file from sharepoint)

Not quite sure what is the problem. Can you please elaborate the topic?SharePoint 2007 - 2010 Tips & Tricks Portal | Microsoft MVP | My Blog about Information Management | My twitter

Ok I have 2 SharePoint computers, accessable from the hostname assigned to the NLB ip address.You click on a document in the document library, there is a HttpHandler that opens a WPF browser application. The WPF calls a WCF service hosted on the same SharePoint computers (endpoint is again the NLB hostname)The WCF service downloads the clicked document from the document library with WebClient.DownloadString(nlbAddress + filename) and returns the content to WPFHowever, instead of returning the file content I get:WebException remote server returned 500 Internal Server ErrorStack: DoNegotiate() etc, etc.This situation is totally working when not using the Network Load Balance

Not sure how this relates to the SharePoint. However, can you debug your WCF server to detect where it fails - on downloading file (not accessing the list) or returning file to the client? I reckon WCF forum is the best place for WCF questions http://social.msdn.microsoft.com/forums/en-US/wcf/threads/SharePoint 2007 - 2010 Tips & Tricks Portal | Microsoft MVP | My Blog about Information Management | My twitter

I am so terribly sorry, I noticed my WCF service wasn't running properly on one of the computers.Didn't think that was the problem but somewhere between sharepoint applications with delegation.Maybe you can suggest a (free/trial) tool to test the load balancing?