I was asked to create a web interface front-end with Microsoft Dynamics CRM as back-end. But I had some troubles setting up the connection, since it has to be done using a domain logon. This doesn't have to be a problem at all, unless your configuration is wrong! In this article I'll explain a few things and point you in the right direction when you have login problems.
As stated earlier, the server running the PHP installation is not Microsoft. In this case a AS400 installation, but it could've been a Linux installation also. I'm using PDO for this article and PHP version 5.2.11. Even if you don't want to use PDO, I recommend using it only for debugging (if possible) since that will give you *most likely* more debug information then the mssql_* family.
When using PDO with a MS-SQL database, you'll need to supply "dblib" as driver and DBLib uses FreeTDS as underlaying library. FreeTDS can be a source of troubles when you're trying to connect, if not configured properly. So I'll kick-off with a little information about it. Don't skip it if you have login problems!