We are currently shifting from using PostgreSQL installed on remote CentOS boxes to using MS SQL Server 2008 R2 installed on remote Windows Server 2008 R2 boxes.
Our web application that uses this database is installed and running on another CentOS box where it will remain.
All of these boxes are provided by a 3rd party hosting provider and are all on the same domain network.
Our development is therefore remote from the server/database domain as our development machines are remote. In the past opening a VPN was enough to allow our development instances of our web app running locally on our PCs to connect remotely to the PostgreSQL database running on the CentOS box.
However now we are having trouble doing the same with the Windows Server 2008 R2 box. Even with the VPN open any attempt to connect (or even ping) the remote server machine times out.
Our code to get a connection to the database instance on the new database server is correct as when we upload that code onto the CentOS application box and run it, it connects fine, as the code is now running on a box in the same physical domain as the Windows Server 2008 R2 box. However we need to make a connection from remote development machines.
Does this make sense?
Are there some windows firewall settings we need to change to allow remote connections?
As I said, we can’t even PING the new Windows Server 2008 R2 machine from remote boxes.
Combined with tips from the other answers and help from our hosting provider we managed to sort this out. It was mostly an issue of those ports being blocked by our provider.