"Login failed for user (null)" - vpn windows authentication

  • I vpn from a workgroup to a domain (requiring login), and on connecting to sqlserver via odbc or EM, I get the error: "Login failed for user ('null')".

    Meanwhile, other apps requiring vpn connection (netmeeting for example) work.  I can login using sqlserver authentication, and this is the work-around for now.

    Meanwhile, from another workgroup site (my home - wireless LAN), windows authentication works great.  I used the same laptop at both workgroup sites, with the same configuration, except that I traded out the ethernet for a wireless card.

    So I figure it must be a workgroup configuration problem (not the domain & not the computer).  Any ideas as to what the exact problem might be?

    Data: Easy to spill, hard to clean up!

  • For SQL Server to use Windows Authentication, it has to be with a trusted network. With the error you are getting, I would guess that the system you are on is not a trusted domain.

    -SQLBill

  • It's odd that at my home the authentication works from the vpn login, and from the work site it doesn't.  One clue might be that the work site used to have a domain, although now it is a workgroup.  Perhaps some old configuration remains & is getting in the way?

    To act on this, I need something specific to check, as there is unfortunately no network specialist available in the office. 

    How is a trusted domain established?

    Data: Easy to spill, hard to clean up!

  • Usually all the computers are in the same domain. If not, then the logins/passwords are being authenticated by the same domain controller. So, I believe your worksite computer needs to be in the DNS on the domain that SQL Server is part of. Then your login/password would be recognized by the domain and access given to SQL Server.

    Are you using the same login and password on all the machines?

  • Yes, it's the same login & PW for VPN.  At home, where it works,  I use a wireless card.  At work I use an Ethernet 10/100 LAN PC Card.  Otherwise it's the same config on the same computer.

    Data: Easy to spill, hard to clean up!

  • Have you checked the SQL Server Error logs and the Windows Event Viewer Logs for any error messages that might give more of an insight?

    -SQLBill

  • I'm not sure why it works from one workgroup and not from another workgroup but below is what we do connecting to different domains using windows authentication. Paste this code in a bat file and you can just execute the bat file whenever your want to.

    runas /netonly /user:domain_name\user_name "mmc /s \"C:\Program Files\Microsoft SQL Server\80\Tools\BINN\SQL Server Enterprise Manager.MSC\""

     

    (The location of SQL Serer console is the default location above. Please change the location if its not the default in your case..)

     

  • I haven't tried it yet, but I notice there's no place for the PASSWORD.

    On the workstation you are having problems with, can you use that to get to any other computer?

    -SQLBill

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