Linux上的PHP随机无法连接到Microsoft SQL Server 2005

(Not a Linux guru!) At work we have for the past month had a serious issue that we haven't been able to solve. From a server running Ubuntu-Linux we are using PHP to connect to a server running Microsoft SQL Server 2005. This has been working without problems for a long time. At the start of February 2013 we moved the SQL Server machine into the same core network as the Linux-machine, which involved changing IP-address on the Windows-server running SQL Server 2005.(Not a Linux guru!) At work we have for the pas