apache does not prevent you to access a MsSQL svr, I even remember a thread dealing with the
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the awfull thing with mssql is not its not-compliant-with-not-ms-products side, that is usual, it's more its login weakness;
no way - as far as I know, and I'm ready to learn - to perform connection over a asymmetric ciphered channel (such as SSH). Edit: look like I didn't update my svr for a too long time.
that point to highlight that a) connection to MsSQL are safer if the web server and the mssql server are the same host, and b) in this case for sure, apache (& PHP module, & any modules) can connect to it w/o trouble.