I have an IIS6 box w/ PHP installed. One of the php pages requires a connection to a remote MySQL 5 box (same subnet, so no fw issues).With this same user on the MySQL box itself, I can connect ...

If you need to allow remote connections to your MySQL server, see how you can easily accomplish that task.

Do you have problems accessing a MySQL or MariaDB Linux server on your local network? If so, you may need to change a few settings and files.

Create a MySQL user (with select, lock tables privileges) on the database machine that only accepts connections from the remote backup machine.