ODBC on a remote server

Hi all! I want to connnect from Server "A" to SQL-Server "B" through ODBC. I have read several threads on the list about this, but it's not clear to me, if it can or cannot be done? If I set up an ODBC-Datasource on "A" referring to "B", everything seems to work fine, but if I want to use the connection with PHP, I get the error message: Warning: SQL error: [Microsoft][ODBC SQL Server Driver][SQL Server]Login failed for user 'NT-AUTORITÄT\ANONYMOUS-ANMELDUNG'., SQL state 28000 in SQLConnect in ... the $_SERVER['AUTH_USER'] variable is not empty, so I don't understand, why is it : ANONYMUS. 2. I thought that I could use the ODBC-Data Source on the SQL-Server, but I don't know how to refer to it. Is it possible? Can someone help me? Regards, Gabor