Microsoft SQL Server is known to be a target for brute force attacks when it is publicly accessible, therefore it is best practice to lock down remote access to specific IP addresses, use a VPN or at the very least use an alternate port so that port scanners looking for port 1433 being open will not find it.
If you do not have a static IP address, and only a small number of people require remote access, then we recommend using our VPN solution.
For customers hosted with us via our default provider, we also have an alternate MSSQL port available for use in our network firewall. The port # is 14330
You can change the port in which MSSQL listens on by open up the SQL Configuration snap-in and changing the TCP/IP settings and restart SQL, show below:
Alternately you can use port forwarding, allowing you to keep MSSQL running on the standard port for local connections, but an alternate port for remote connections.
See the following article for port forwarding on windows, http://woshub.com/port-forwarding-in-windows/
Then, make sure that port 14330 is open in your Windows firewall.