Any way to find out who's causing "Login failed for user '(null)'. Reason: Not associated with a trusted SQL Server connection. " error in SQL Server error logs?

Thanks

https://social.msdn.microsoft.com/Forums/sqlserver/en-US/9960cce7-bf46-45d2-918c-808500a5c246/login-failed-for-user-null-reason-not-associated-with-a-trusted-sql-server-connection?forum=sqlsecurity

Will record in error log.check de

The link did not helped at all. I do not know where it's coming from; nor, has anyone reported issues. I am trying to find out more information about where and whom is trying to connect that is causing the error in my error logs.

Is it hacker? Is it mistakes from internal personnel?

You could try setting up a trace that captures the Audit:Login Failed event, and see you can make something out of the information you capture. Note that hostname and application names can be set in the connection string, so they don't have to be authentic.

http://blog.sqlauthority.com/2007/04/14/sql-server-fix-error-18452-login-failed-for-user-null-the-user-is-not-associated-with-a-trusted-sql-server-connection/

http://blog.sqlauthority.com/2007/04/14/sql-server-fix-error-18452-login-failed-for-user-null-the-user-is-not-associated-with-a-trusted-sql-server-connection/

Dinesh, I understand that you want to help, but can you please read the questions and stop acting like a robot program that reacts on keywords? Ami is not asking how to fix the login problem. He is trying to figure out from where these login attempts are coming.

Thank you Erland. Unfortunately, I do not have a running trace going. And it's not a daily occurrence that to set a trace. It's pretty random.

Nevertheless, thank you for looking and answering.

If it's only random and no one is reporting a problem, I would not bother. Or are these message coming big droves on the days they appear?