MSSQL over the internet but we connect over RDP We connect throguh RDP to our ERP solution which uses MSSQL 2008, right now I can see on windows logs and SQL logs that we have a HUGE amount of connection attempts to sa user and results in slow connections to us, users.

Since we connect through RDP and both ERP and DB are on the same server, I think I can close SQL port to the internet, and that would stop direct attacks to the DB, but our IT consultant it's not sure about it. I think it's safe to say that the only ports needed to be open through internet are RDP ports, besides that all happens in a LAN enviroment.

Am I right or am I missing something?
I wrote a blog post about the perils of having your SQL Server exposed to the internet.  

You should almost never allow internet access directly to SQL Server.  From your description, it sounds like you have no requirement for that, since you RDP into the machine for access.  I would immediately ensure the port used by the SQL Server is blocked at the firewall.