title: Using cached credentials to connect to SQL 2005 across a domain boundary
body: <p>Ever since moving to Vista some time ago on my development machine, connecting to SQL Servers in our DMZ active directory domain from client tools like SSMS has not worked like it used to.  In XP, as long as I had authenticated in some way on the server (for example directing Explorer to \server.dmzdomain\c$ and entering valid creds into the login prompt), SSMS would use those cached credentials to connect.</p>
  
  <p>However since switching to Vista, when trying to connect SSMS to a server in the DMZ domain I get the message <em>Login failed for user ''. The user is not associated with a trusted SQL Server connection.</em>  If I change the connection options to use Named Pipes instead of the default TCP/IP, my cached credentials are sent and everything works fine.  This is the case whether Windows Firewall is off or on, and connections to servers in our internal domain (the same domain my dev PC is in) work fine over TCP/IP or named pipes.</p>
  
  <p>I don't mind too much using named pipes for these connections as a workaround, but it seems like TCP/IP is the recommended connection method and I don't like not understanding why it's not working as I'd expect.  Any ideas?</p>