We've got a client that we're going to allow to use one of our applications. Staff on site regularly connect to our network via VPN. The .Net application that connects to the SQL Server uses integrated security. The laptops they use are members of our domain.

The client has requested use of the application as well. So we gave them a network account and the ability to create a VPN session on our network. I gave that account a login on the SQL server with the same rights as our own staff.

The problem is that when they try to use the application they get the following error: The login is from an untrusted domain and cannot be used with Windows authentication.

I'm guessing that since they are using a computer that is not on our domain, it doesn't matter that they are using a login with the VPN that is. So, what is the best way to address this problem? I'd rather not switch over to SQL authentication for this small application.

  • Hi - if you want to migrate this over to security.stackexchange.com you should get some useful answers.
    – Rory Alsop
    May 10, 2011 at 20:39
  • So, the word I'm getting from network folks is that because of the way that cisco works this is probably not going to work. SQL authentication it is.
    – RThomas
    May 11, 2011 at 15:51
  • problem fixed using sql authentication? May 12, 2011 at 6:48
  • Yes, I switched to sql authentication after network guy helped me understand how the server sees the incoming VPN user and realized it wasn't going to work they way I wanted it to.
    – RThomas
    May 12, 2011 at 17:52

1 Answer 1


If the client computer isn't on the same domain as the SQL Server, and if there's no trusts set up between the client computer's domain and the SQL Server's domain, you can't use integrated authentication.

  • I hesitate to mark your answer as correct for the simple fact that I want to hold on a little longer to the time when my "street cred" on this forum was higher than yours... but alas, it'll happen soon enough I guess.
    – RThomas
    May 27, 2011 at 19:58
  • @lazyDBA - HAHAHA, nice.
    – Brent Ozar
    Jun 8, 2011 at 16:44

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