Webdav failing to use integrated authentication since domain migration

Question

We have a program that uses webdav, authenticating with windows authentication so users don't have to type their username and password. this worked fine until we migrated domain. now the code that used to connect returns error code 5 (access denied):

string psPassword =null, psUsername=null;
structNetResource stNetRes = new structNetResource();
stNetRes.iScope = 2;
stNetRes.iType = RESOURCETYPE_DISK;
stNetRes.iDisplayType = 3;
stNetRes.iUsage = 1;
stNetRes.sRemoteName = WebDAVServerpath;
stNetRes.sLocalName = null; //connect, but don't show drive in my computer
int iFlags = CONNECT_CMD_SAVECRED;
int i = WNetAddConnection2A(ref stNetRes, psPassword, psUsername, iFlags);

Does anyone have any idea how to fix this? I've tried running

int j = WNetCancelConnection2A(WebDAVServerpath, CONNECT_UPDATE_PROFILE, 0);

beforehand to clear any old connections but this isn't working.

(Running net use \\server.domain.com\share now prompts for a username and password whereas before it used to connect straight away, so it looks like something's interring with windows authentication.)

Edit - This is a WinForms application, IIS and the shared files are stored on the same machine. The problem only occurs on machines that were migrated; PCs that were (and still are) outisde our domain are unaffected.

Answer 1

If your file server and web server are not the same machine, you need to set up the file server to trust the web server for delegation. This allows the file server to trust the credentials that the web server has authenticated instead of re-prompting for credentials on each request.