Creating links between databases on different machines

Last year I worked on an interface between two systems to synchronize the data. It was specked out so that it was restricted to work with databases on the same machine or on different machines within a LAN, by specifying the machine name.

As it's been sold to a customer trying to connect two machines over the Internet by specifying an IP address. I've got to do a quick change to enable this.

Here's a quick list of situations to test in such a situation:

• server specified by machine name
• server specified by IP address
• databases on the same machine
• databases on different machines in the same domain in the same LAN
• databases on different machines in the same domain in the same WAN
• databases on different machines in different domains, but in the same LAN
• databases on different machines, connected over a VPN
• database on different machines, connected over the Internet
• connections using network/user authentication
• connections using specified a user name and password

Why does this matter?
Because connection strings may need to be different.