Talk:FreeTDS

Login failed for user '(null)'. Reason: Not associated with a trusted SQL Server connection.
This issue is not covered under the SourceForge FAQ, and I hope this helps someone as it was a difficult one to work out.

Explanation (Reference NTLM)

Microsoft adopted Kerberos as the preferred authentication protocol for Windows 2000 and Windows 2003 Active Directory domains. Kerberos is typically used when a client belongs to a Windows Server domain, or if a trust relationship with a Windows Server Domain is established in some other way (such as Linux to Windows AD authentication). If using Kerberos, it is vital that the system times on both client and server are within a few seconds of each other, otherwise Kerberos authentication will fail.

However, NTLM (NT LAN Manager) is still used in the following situations:

•	The client is authenticating to a server using an IP address.

•	The client is authenticating to a server that belongs to a different Active Directory forest, or doesn't belong to a domain.

•	No Active Directory domain exists (commonly referred to as "workgroup" or "peer-to-peer").

•	Where a firewall would otherwise restrict the ports required by Kerberos (of which there are quite a few)

When the user is “null” this means Windows was unable to pass the credential, which actually means a network security restriction. The jTDS driver that Java uses to connect to MSSQL fails with this error message when forced to use NTLMv2 challenge-response authentication protocol. NTLMv2 is similar to NTLM but with enhanced security settings such as the use of complex password patterns and better encryption.

Solution

On the SQL server you are connecting to, check that the time is in sync with your client (kerberos) and also that NTLMv2 security is not enabled.

To do the latter run gpedit.msc and browse to Computer Configuration \ Windows Settings \ Security Settings \ Security Options.

Have a look at Network security: LAN Manager authentication level and make sure this is not using any form of NTLMv2.

The Windows Server default is actually “Send NTLM response only”.

Karlburgdorf (talk) 14:57, 28 July 2008 (UTC)

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